LONDON — Britain should "think again" about taking part in airstrikes on Islamic State jihadists in Syria, Defence Secretary Michael Fallon said on Monday, after attacks in Paris that left at least 129 people dead.

"We have to think again about how we can help hit ISIL (another term for IS) harder and that leads inevitably to considering strike operations in Syria," Fallon said.

IS has claimed responsibility for the coordinated attacks in Paris on Friday and French President Francois Hollande has called them an "act of war."

Britain is taking part in strikes on IS targets in Iraq and the government wants to seek parliamentary approval to extend these to Syria if it can secure a consensus across parties.

However, the left-wing leader of the main opposition Labour party, Jeremy Corbyn, is opposed to any such action.

"France's fight is our fight and we've made it very clear to them this terror is just two hours away, it's on our doorstep," Fallon said on Monday.

"Their fight is our fight and we have to now look at all the options to help join in that fight," he said, adding that France, Turkey and the United States would "welcome" British involvement in the campaign.

Fallon referred to a previous vote in 2013 when Prime Minister David Cameron's previous government suffered a scarring defeat over its plan to join international military action over the Assad regime's use of chemical weapons in Syria, due to Labour opposition.

"We have made it clear we need the consent of parliament to do this and we need to build that agreement amongst MPs," Fallon said.

"It's a new parliament since the vote two years ago. That vote was before ISIL began its campaign and it was on a slightly different issue. But we have to persuade enough MPs that you simply can't now rule out any military option," he said.

Asked about the possibility of a vote on airstrikes, Cameron told BBC radio Monday: "I need to build the argument, I need to convince more people, but in the end parliament must decide."