Appearing on BBC One’s The Andrew Marr Show, the Labour leader questioned the legal basis for the UK joining the US and France in airstrikes in response to the chemical weapons attack in Douma.
It came as Boris Johnson said “there is no proposal on the table at the moment for further attacks” in Syria. The Foreign Secretary also appeared on the BBC One show on Sunday.
Asked if he would order military action in any circumstances if he was prime minister, the Labour leader replied: “No-one would ever say never.”
But Mr Corbyn said Parliament should have been given a vote ahead of the strikes.
“I think what we need in this country is something more robust like a War Powers Act so that governments do get held to account by Parliament for what they do in our name.”
Mr Corbyn said that if Britain wants to “get the moral high ground around the world” it must abide by international law for taking military action.
Asked if there were any circumstances in which he would back airstrikes in Syria, Mr Corbyn replied: “I can only countenance involvement in Syria if there is a UN authority behind it.
“If we could get to a process in the UN where you get to a ceasefire, you get to a political solution, you then may well get to a situation where there could be a UN force established to enforce that ceasefire.
“That surely would save a lot of lives.”
The US has warned it is “locked and loaded” if Syria carries out fresh attacks on its people.
Mr Corbyn said: “President Trump has a way with words, that’s for sure. I hope it’s just exaggeration on his part.”
Meanwhile Mr Johnson said “finally the world has said enough is enough” as he defended the “proportionate” action in Syria.
He told the programme: “There is no proposal on the table at the moment for further attacks because so far – thank heavens – the Assad regime has not been so foolish to launch another chemical weapons attack.”
Mr Johnson added: “If and when such a thing were to happen then clearly, with allies, we would study what the options were.”
The Foreign Secretary, when asked if Syrian President Bashar Assad still has chemical weapons capability, replied: “I can’t answer that question. Clearly the strikes were successful on three important sites.
“But the overwhelming purpose, the mission was to send a message that after years now in which we’ve seen a series of chemical weapons strikes – four of them authenticated by the OPCW joint investigative mechanism, dozens of other attacks of which we have testimony – finally the world has said enough is enough.”
Additional reporting by Press Association.