Jeremy Hunt has said the UK may need to delay Brexit beyond the planned date of March 29.
The foreign secretary said on Thursday morning it was “difficult to know” how long negotiations with the EU would run.
“If we ended up approving a deal in the days before 29 March, then we might need some extra time to pass critical legislation,” Hunt told BBC Radio 4′s Today programme.
“We can’t know at this stage exactly which of those scenarios would happen,” Hunt said.
Hunt added: “There are lots and lots of hurdles, no-one is saying this isn’t going to be very challenging, but we do now have a consensus in parliament.
“We can use that consensus, providing we can meet these concerns, very reasonable concerns from our friends in Ireland about not having a hard border, concerns in the EU about access to the single market.
“Providing we can do that, which I think we can, then I think there is a way through.”
It came as business secretary Greg Clark urged May to reach out across the political divide to secure a Brexit deal that can command a “substantial” Commons majority.
Clark – who strongly opposes a no-deal break – suggested ministers should be prepared to a listen to calls for a customs union with the EU, even though it runs counter to government policy.
Amid reports that a swathe of ministers could resign in the event of no-deal, Clark said he would do “everything that I can” to prevent a “disorderly” withdrawal from the EU.
Meanwhile, the Institute for government (IFG) said the UK is unprepared for a no-deal exit as it warned there would be “extremely damaging” disruption.
The think tank predicted that in eight out of 11 broad policy areas, including health and borders, the government would be unable to avoid some “major negative impacts”.
May is due to report back to parliament on her negotiations with the EU on February 13, with a further series of votes by MPs expected the following day.
Reports have suggested she could face a wave of resignations by pro-Remain ministers if she does not at that point finally rule out a no-deal Brexit.