EU law and Article 50 supersede the Benn Act, Leader of the House Jacob Rees-Mogg has said.
Speaking on the recording of the Conservative Home podcast, Moggcast at the Conservative party conference in Manchester, Mr Rees-Mogg said the situation was "very straightforward".
Despite this, Mr Rees-Mogg also admitted he does not see any "easy and obvious loophole" the Government could use to get around the Benn Act.
The Benn Act says the Prime Minister must ask the EU for an extension of the Article 50 negotiating period by 19 October, unless Parliament has approved a deal or a no-deal Brexit.
When asked by a member of the public at the fringe event whether EU law and Article 50 supersede the Benn Act, Mr Rees-Mogg said: "Yes it does, so it's very straightforward."
Mr Rees-Mogg continued: "You may remember how we got the extension from 29 March.
"We did not get it by an Act of the UK Parliament, we got it because as long as the 1972 European Communities Act is enforced, EU law is more powerful than UK law.
"So anything that is agreed at the EU level is our fundamental law overriding any domestic legislation.
"So Article 50 and EU law overrides the Benn Act, and if Dominic Grieve were here he'd say the same thing."
Mr Rees-Mogg was also pushed by an audience member on how the Government could get around the Benn Act, which requires the Prime Minister to write a letter to the EU requesting an extension.
On possible legal loopholes the Government could exploit to avoid implementing the terms of the Benn Act, Mr Rees-Mogg added: "The law is the law as it is.
"There is the very important question of how it interacts with EU law, but there is no easy and obvious loophole that I can sit here and tell you we can use, because if there is I haven't spotted it."
Mr Rees-Mogg also told Conservative party members the 21 former Conservative MPs who had the Tory whip removed after voting against the Government should have the whip restored if they can show they are willing to support the Government to deliver a Conservative programme.
He said: "I always believe in politics in being as generous as you possibly can be.
"But you cannot have a situation where people are trying to put Jeremy Corbyn in charge of the order paper.
"So, look, if they are willing to show that they are willing to support a Conservative Government deliver a Conservative programme, and pull back from what they did before, I think generosity is in the nature of Conservatism, and the Conservative party is a broad church and needs to remain a broad church."
He continued: "Therefore we ought to be generous and we oughtn't to be ideological about who belongs to the Tory Party, we need to welcome people who are willing to make interesting arguments, but we cannot have a situation where people hand over the order paper to the Opposition.
"So how do we get on from here? Well, let's see if there are any other votes which give them the chance to come back, but I think a number of them are retiring and have no interest in coming back, so it won't be everybody."