The row threatened to overshadow the start of five days of debate in parliament on May's Brexit deal ahead of a crucial vote on December 11, when lawmakers will be asked to approve it. Opposition parties say they will vote against it, as do dozens of lawmakers from May's Conservatives.
"I'm focusing on ... getting that vote and getting the vote over the line", she said.
Attorney General Geoffrey Cox will also reveal to MPs highly-anticipated legal advice on the Brexit backstop.
The row came after Theresa May told Tory MPs to "hold their nerve" and back her Brexit deal, insisting she would still have a job in two weeks' time as she faces a crunch December 11 Commons vote on her EU Withdrawal Agreement.
She said she had spoken with Japanese investors in the United Kingdom, adding: "One of the key messages they have given is about the importance of being able to maintain a good trade relationship with the European Union when we have left".
With the odds looking stacked against her, May is touring the country and media studios to try to win over critics including both eurosceptics and europhiles who say the deal will leave Britain a diminished state, still linked economically to the European Union but no longer with a say over the rules.
"That's what the deal that has been negotiated delivers".
The government says that if May's deal is voted down there is a risk Britain will exit the European Union with no agreement at all, with serious potential economic consequences.
In a letter to the prime minister, Oliver Robbins said the backstop, intended to prevent the return of a hard border with the Republic, would mean the imposition of regulatory checks between the North and the rest of the United Kingdom, according to The Daily Telegraph.
"That is the message we have consistently given since the bad murder of Jamal Khashoggi and it is a message we will continue to give".
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"When you take all these red lines into account, it's simply impossible to come up with something different than we have now, the deal on the table", he told The Associated Press on the sidelines of a United Nations climate conference in Poland. This would be a collision course between the government and parliament, ' he told Sky News.
MPs across Parliament have angrily accused ministers of ignoring the will of the House after they said only that they would release a "full reasoned political statement" on the legal position.
The government said after the vote that it would now publish the full advice.
"Although I accept the long-standing convention that Cabinet legal advice should be kept confidential, it's well-established that in exceptional circumstances that convention does not apply". Opposition parties suspect it will only offer a summary of that advice.
House of Commons Speaker John Bercow agreed late Monday there was an "arguable case" that contempt had been committed.
Around 100 anti-Brexit campaigners turned out for a demonstration near Downing Street on the eve of the start of the parliamentary debate on the Brexit deal.
Lawmakers can send the issue to a committee with the power to sanction ministers.
Earlier, Mrs May's chief Brexit adviser told MPs the border backstop was a "slightly uncomfortable necessity" for both the United Kingdom and the European Union.
"I make no bones about it - I would have preferred to have seen a unilateral right of termination in this backstop", he told MPs.
"What is being presented to the public as a sensible compromise Brexit deal, a 52/48 Brexit as some call it, will not bring closure or heal the divisions of Brexit", he said.