Prime Minister Boris Johnson should offer parliament an unequivocal commitment he will not lead Britain out of the European Union without a deal if he wants backing for an early election bid, Labour's home affairs spokeswoman said on Sunday.

Diane Abbott reiterated Labour's position on the BBC's Andrew Marr Show that the opposition party cannot back the election bid until it is sure a so-called no deal Brexit is off the table.

"One way of doing it is for Boris Johnson to come to the floor of the house and give the House of Commons (lower house of parliament) a commitment that whatever happens, he will not take Britain out of the EU without a deal," she said.

"If he said clearly and unequivocally that 'I will not take Britain out of the EU without a deal', I think not just the Labour Party would be satisfied ... a lot of Conservative MPs (members of parliament) would be satisfied."

"Let's wait to see if he does that."

* Reuters