In a statement this afternoon, a spokesperson for Labour leader Jeremy Corbyn said: "Today's shadow cabinet agreed to back Jeremy Corbyn's recommendation of a free vote on the Government's proposal to authorise UK bombing in Syria."
Under the free vote, Labour MPs will be allowed to vote for or against the government's proposals without being forced to resign or fear of being sacked by Corbyn, who opposes the government's proposed air strikes.
"The shadow cabinet decided to support the call for David Cameron to step back from the rush to war and hold a full two day debate in the House of Commons on such a crucial national decision," Corbyn's spokesperson added.
Earlier today, Corbyn wrote to Prime Minister David Cameron asking for a two-day debate on air strikes in Syria.
In a letter sent this afternoon beginning "Dear David", Corbyn said the matter is "of such critical importance there must be full and adequate time for any debate".
"A one day debate would inevitably lead to important contributions being curtailed," Corbyn said, adding the debate would be "much better informed" if it included views from the foreign affairs and defence select committees.
Downing Street has repeatedly said that Cameron will not call a Commons vote on extending British anti-ISIS air strikes to Syria unless he is sure he has a clear majority of MPs supporting him.
With the Prime Minister in Paris today for climate change talks and expected to be out of the country on Thursday and in his constituency on Friday, most have expected the vote would come on Wednesday.
Corbyn is expected to face criticism from anti-war groups, including the Stop the War Coalition, which said earlier today that it opposed having a free vote and instead wanted Corbyn to impose a "three-line whip" forcing Labour MPs to vote against the government's proposals.
Also earlier today, Corbyn's office released an internal poll showing 75 per cent of Labour members are against strikes in Syria.