PARIS - Tax authorities from the world's richest nations on Wednesday probed a mass of murky offshore dealings revealed in the huge Panama Papers data leak, just hours after police raided the law firm at the centre of the scandal.

The leak of 11.5 million confidential offshore financial documents from Panamanian law office Mossack Fonseca offered international tax officials meeting in Paris an unprecedented trove of data to delve into alleged wrongdoing, officials said.

"We are basically trying to get the bigger picture," Australian Tax Commissioner Chris Jordan, who proposed a joint investigation, told the Australian Financial Review business daily ahead of the gathering. "It has never been tried on this scale before," Jordan added.

"A number of countries have got slices or pieces of the data and that's been very useful, but really, the start of the conversation is to work out who's got what, how we can pool that information and start to work together."

Australia convened the closed-door meeting in the French capital as chair of the Joint International Tax Shelter Information and Collaboration Network, which seeks to crack down on cross-border tax cheats.

The global network looking into tax havens is an initiative of the Paris-headquartered 38-nation advanced economies club, the Organisation for Economic Cooperation and Development (OECD).

"The meeting at the OECD presents tax administrations with a first opportunity to act on the considerable body of information revealed by the Panama Papers release," the OECD said in a statement in the run-up to the one-day gathering.

The tax officials gathered behind closed doors in Paris just hours after the Panamanian police's organised crime police raided the headquarters of Mossack Fonseca, which says its confidential documents were stolen in a computer hack.

Prosecutors said the raids at Mossack Fonseca's headquarters in Panama City and other branches had taken place "with no incident or interference," but gave no details on the results of the searches.

The world's business, political and even sports elite have been thrown onto the defensive by the findings of a year-long probe by a consortium of investigative journalists into leaked documents covering almost 40 years from around 214,000 offshore entities.

Although not illegal in themselves, offshore financial transactions may be used to hide assets from tax authorities, launder the proceeds of criminal activities or conceal misappropriated or politically inconvenient wealth.

Hunting tax evaders identified by the Panama Papers leak requires a global response, a top Australian official has said, proposing a joint investigation by 28 countries to pool data, according to a report on Wednesday.

The plan by Australian Tax Commissioner Chris Jordan, who has a reputation for his direct approach to multinational companies over their tax affairs, will be discussed at a meeting of global tax officials in Paris, the Australian Financial Review said.

Iceland's prime minister was forced to resign after it emerged he owned shares in the country's banks through an offshore company during the financial crisis.

Leaders in Britain and Ukraine have faced questions over their taxes, while Russian President Vladimir Putin has sought to divert attention from his entourage by claiming it is all a US plot against him.

China has been censoring online forums and media to stifle discussion of the papers, which showed relatives of eight of its political top brass also owned offshore companies.

And wealthy citizens in Australia, France, India, Mexico, Peru, Spain and elsewhere face probes over suspected tax avoidance after their names figured in some of the documents.

Panama has hit back at the apparent blemish on its image. It has warned France of unspecified diplomatic measures if France does not remove it from a blacklist of tax havens.

Paris put Panama back on its national list of uncooperative jurisdictions, after removing it in 2012, in the wake of the leaks.

France is also urging the European Union and all OECD member states to follow suit.

Such an international designation would deal a heavy blow to Panama's vital financial services sector, which the government has been trying to make more transparent.

The European Union unveiled plans Tuesday to force the world's biggest multinationals to faithfully report earnings and pay their fair share of taxes, saying the Panama Papers scandal demonstrated the need for change.

Its executive arm said that under the new rules, big companies operating in Europe would have to make public what they earn in each member state of the 28-nation bloc.

Country-by-country reporting has been a major demand of tax activists who accuse big corporations of secretly shifting profits to low tax jurisdictions, often using shell companies such as those exposed in the Panama Papers leaks.

Jordan said a six-country collaboration he set up in 2012 to investigate the world's largest e-commerce companies was the prototype for the Panama Papers probe.

"We're basically trying to get the bigger picture," he told the newspaper. "It's never been tried on this scale before.

"A number of countries have got slices or pieces of the data and that's been very useful, but really, the start of the conversation is to work out who's got what, how we can pool that information and start to work together."

The meeting to thrash out a global strategy will be convened by Australia on Wednesday as chair of the Joint International Tax Shelter Information and Collaboration (JITSIC) network - part of the Organisation for Economic Cooperation and Development (OECD).

The explosive leak of 11.5 million documents from Panamanian law firm Mossack Fonseca earlier this month revealed the confidential dealings of world leaders, celebrities and sports stars.

The scandal has already caused the Icelandic prime minister to resign while several countries, including Australia, have opened legal probes following the revelations.

Of the more than 800 Australians listed in the Mossack Fonseca files, 80 of them are linked to serious and organised crime, the newspaper said.

The documents were exposed in a global media project led by the International Consortium of Investigative Journalists.

The Financial Review said the organisation plans to release the names of all of the 240,000 offshore entities set up by Mossack Fonseca, along with directors and shareholders, next month.

That would provide tax authorities with names to pursue in tax information exchange agreements.

"There needs to be agreement on pooling information, on collaboration, and a framework to go forward," Jordan said of Wednesday's meeting, which the ATO's head of international tax Mark Konza will chair.

"I did encourage other commissioners to send similar people of senior level," he added.

"And then it will be devolved to more operational people in the JITSIC network. It's got to be the right sort of people - not transfer pricing, not international tax specialists. It's data analytics people we need."