TOKYO - Japanese lawmakers late Thursday started what is set to be a marathon debate over controversial security bills after scuffles broke out in parliament and protesters railed against the measures.

Parliamentarians gathered for a plenary shortly after 8:00 pm (1100 GMT) ahead of a vote that could see Japanese troops fight on overseas soil for the first time since World War II.

In fraught scenes uncommon for Japan’s normally sedate parliament, opposition lawmakers earlier on Thursday climbed on top of each other in a bid to stop the chairman of a committee calling a vote on the controversial bills. Twice scuffles broke out, with the suited committee members lashing out at each other, pushing and shoving in a huge scrum that failed to prevent the panel approving the bills.

As the evening wore on, hundreds of protesters braved wet weather outside parliament in plastic raincoats, waving their umbrellas and chanting anti-war slogans.

Earlier, some held up pictures of Prime Minister Shinzo Abe with a Hitler haircut and moustache. Tens of thousands of people have taken to the streets to vent their anger during almost daily rallies in recent weeks, a show of public feeling on a scale rarely seen in Japan.

A total of 13 people were also reportedly arrested on Wednesday for “interfering with officers” during a rally that saw an estimated 13,000 people gather outside parliament in Tokyo.

While it looks like little can now stop the bills, they have taken a toll on Abe’s once high popularity and opinion polls show most voters overwhelmingly oppose them.

Abe and his supporters say the changes are necessary to deal with a changing security environment marked by an increasingly assertive China and unpredictable North Korea.

Opponents say they are unconstitutional and could drag Japan into American wars in far-flung parts of the globe.

If brought in, critics say they could herald the biggest shift in Japan’s defence policy since when Abe’s grandfather was in power 55 years ago.

Under the planned changes, the military - known as the Self-Defense Forces - would have the option of going into battle to protect allies such as the United States even if there was no direct threat to Japan itself or its people.

Although the constitution, which bars troops from taking part in combat except in pure self-defence, was imposed by US occupiers, many Japanese feel strongly that any change in the law would alter the country’s pacifist character.

Tensions were running high in parliament Thursday after the committee vote was repeatedly delayed through Wednesday night, as opposition lawmakers blocked doorways and packed the corridors of parliament in protest.

During the committee session, opposition parliamentarian Tetsuro Fukuyama made an emotional speech outlining why his party had submitted a motion to delay the bills.

“Is the ruling party listening to the voices of the public? You can do whatever you want to do because you have a majority - is that what you think?” he said, on the verge of tears.

But Masahisa Sato, a senior ruling party lawmaker who has promoted the bill, hit back after it was approved by the committee, saying: “This is legislation necessary to protect lives and the happiness of Japanese people.”

Opposition lawmakers were expected to propose a series of censure motions against Abe and his ministers at the upper house plenary session, a delaying tactic that will likely be voted down by the ruling bloc.

Abe is keen to get the bills passed before a three-day holiday next week.

The proposed legislation sailed through the lower house - where Abe’s coalition commands a two-thirds majority - in July.