Jeremy Hunt has described October 31 as a "fake deadline" for Brexit and warned that aiming for it could spark a general election.
The foreign secretary and Tory leadership candidate said he felt that committing to the Halloween date could spark a situation which "would hand the keys to Jeremy Corbyn".
"I think that 31st of October come hell or high water is a fake deadline, because it's more likely to trip us into a general election before we've delivered Brexit, and that would hand the keys to Jeremy Corbyn and then we'd have no Brexit at all," he told the BBC.
His comments came after his rival and leadership frontrunner Boris Johnson challenged him to commit to October 31 or set another date if he would not.
Mr Johnson has said he will commit to Brexit no later than Halloween.
Continuing his bid for the leadership, Mr Hunt also said he is the candidate for the Tory leadership who can be trusted to deliver Brexit.
He told the BBC: "Both Boris and I want to change that deal, and the judgment is, who is the person we trust as PM to go to Brussels and bring back that deal?"
"It's about the personality of our PM. If you choose someone where there's no trust, there's going to be no negotiation, no deal. And quite possibly a general election, which could mean we have no Brexit either."
When asked to clarify these comments, he said he was not suggesting Mr Johnson was untrustworthy.
He added: "I would serve Boris Johnson to the very best of my ability and make his prime ministership a success and I hope he'd do the same for me."
