BUCHAREST: Romania's biggest protests since communism were set for a fifth day Saturday with hundreds of thousands expected to demonstrate against what they see as a government retreat on corruption.

Demonstrators planned to gather in central Bucharest in the afternoon and march noisily with whistles, drums and vuvuzela horns in the national colours to parliament and form a human chain.

On Friday night an estimated 250,000 people demonstrated nationwide calling for the government to repeal decrees decriminalising certain graft offences and freeing corrupt officials from prison.

The scale of the protests came close to Wednesday night, the biggest since 1989 when people power toppled communist dictator Nicolae Ceausescu. He and his wife were executed on Christmas Day.

"The government wants to legalise white collar crime, which is really insidious," Sergiu, 43, a bank employee venting his anger at Bucharest's Victory Square, the epicentre of the protests.

Friday's protest in the capital, which drew around 100,000 people, saw effigies of the government officials in prison fatigues paraded through the crowds to jeers and shouts of "Thieves!".

Protesters acted as pallbearers for a coffin bearing the inscription "Romanian justice" carried through the crowd while others gave a rousing rendition of the national anthem.

"I am not a leftist, I am not rightist. My views are centre-right. But I want respect," said Armand, 34, an economist taking part.

- Government defiant -

The left-wing Social Democrats (PSD) have only just returned to power after handsomely winning elections on December 11 promising to boost salaries and pensions in the EU's second-poorest country.

This was barely a year after protests over a nightclub blaze, blamed on corrupt officials turning a blind eye to fire regulations, killed 64 people and drove the PSD-led government from office.

Now the PSD wants to reduce sentences for abuse of power and make them punishable by prison only if sums involved exceed 44,000 euros ($47,500).

A separate bill would free some 2,500 prisoners on short sentences.

The government says it is bringing legislation into line with the constitution and wants to reduce overcrowding in prisons, and has remained defiant despite the protests.

"We took a decision in the government and we are going to press ahead," Prime Minister Sorin Grindeanu said Thursday.

PSD leader Liviu Dragnea, currently on trial for abuse of power involving a sum that falls below the new ceiling, has hit out at a "campaign of lies and disinformation".

But critics see the measures as a brazenly transparent effort by the PSD to let off some of the many corrupt officials ensnared in an anti-corruption drive of recent years that has won Romania praise abroad.

Earlier this week, European Commission head Jean-Claude Juncker and his deputy Frans Timmermans warned against "backtracking" -- only a week after an EU report praised the government's efforts.

Washington added to the chorus of alarm Thursday, saying it was "deeply concerned" that the new measures "undermine rule of law and weaken accountability for financial and corruption-related crimes".

On Friday, Romania's national ombudsman vowed to invoke the constitutional court, saying it was unclear why the abuse of power decree was urgent.

Demonstrators have vowed to rally daily until February 10 when the contentious abuse of power decree, issued by the government late Tuesday, is due to enter into force.

"I left the country mainly because of the corruption," said protestor Cornelius, 26, "on holiday" in his home country back from Newcastle in England where he works as a video editor.

"I earn the same there as here, the only difference is the corruption. The corruption here has reached limits you cannot believe," he told AFP.