Britain's Brexit Secretary Stephen Barclay has said the UK is not looking to extend the Article 50 exit process and will leave the European Union on 29 March.
The Telegraph newspaper reported that British and European officials are discussing the possibility of extending the UK's formal notice to withdraw from the EU amid fears a Brexit deal will not be approved by the withdrawal date.
"The government's policy is clear on this, the prime minister has said it on many an occasion: We are leaving the European Union on the 29th of March. We are not looking to extend," Mr Barclay told Sky News.
When asked if any politicians in the Conservative Party had changed their minds on opposing British Prime Minister Theresa May's deal, Mr Barclay said: "Some have said they are much more open to but it is obviously challenging."
The newspaper said British officials had been "testing the waters" on extending Article 50, but Downing Street said that the prime minister had always said the UK would leave on 29 March and would not extend Article 50.
It comes as Mrs May looks set to lose a crucial vote, which has been confirmed for 15 January, on a Brexit deal.
With stalemate around Mrs May's Brexit deal, MPs continue to look at ways in which they can use parliamentary powers to influence a process that is increasingly unpredictable.
That will include voting on an amendment today that could curb government spending if the UK were to leave the EU with no deal.
Mrs May's government continues to argue that the way to prevent no deal is to vote through her plan next week.
But many MPs remain unhappy with aspects of it and it currently looks as though it will be defeated.
Separately, Taoiseach Leo Varadkar has said the EU is willing to give written assurances about the Withdrawal Agreement ahead of next week's crucial vote at Westminster.
Speaking to reporters during a trip to Mali, he said: "The summit conclusions at our last meeting in December provided written assurances, but what's happening at the moment is there is close contact between the UK and EU institutions as to whether a further set of written guarantees, explanations and assurances could make a difference.
"Our intent, once the Withdrawal Agreement has been ratified by Westminster and the European Parliament, is to get into talks on the future relationship on the new economic and trade treaty with Britain, on the new security partnership with Britain.
"We don't want to trap the UK into anything - we want to get onto the talks about the future relationship right away.
"I think it's those kind of assurances we are happy to give."
Additional reporting Fiona Mitchell, PA