The prime minister is expected in Northern Ireland on Monday as efforts to break the political deadlock at Stormont intensify.
Boris Johnson will hold talks with party leaders and attempt to persuade the Democratic Unionists to enter the power sharing government.
Sinn Fein is now the largest party but its vice president, Michelle O’Neill, cannot become first minister without a Unionist deputy first minister.
The DUP has blocked the formation of a new devolved administration over the Northern Ireland Protocol and resulting sea border.
Boris Johnson may be forced to choose between a government in Belfast or the treaty he agreed with the EU.
Writing in the Belfast Telegraph, the prime minister said: “Many things have changed since the protocol was agreed.
“We have been told by the EU that it is impossible to make the changes to the protocol text to actually solve these problems in negotiations – because there is no mandate to do so.”
Committing to “keep the door open to genuine dialogue”, he echoed the words of Ireland’s foreign minister Simon Coveney and referred to a potential “landing zone”.
“Our shared objective must be to create the broadest possible cross-community support for a reformed protocol in 2024,” he added.
Boris Johnson said he hoped the EU would change its position but warned: “If it does not, there will be a necessity to act.
“The government has a responsibility to provide assurance that the consumers, citizens and businesses of Northern Ireland are protected in the long term.”
“We will set out a more detailed assessment and next steps to parliament in the coming days,” he added.
The government is preparing to publish legislation to override the protocol but Sky News understands there are still concerns in cabinet about the legal position.
The bill could be challenged in parliament or in the courts if it is deemed to have breached international law.
The inclusion of protections to avert that would limit any action to the constraints of the full Brexit Withdrawal Agreement.
Sir Jeffrey Donaldson MP, DUP leader, said: “The prime minister’s visit to Northern Ireland is a recognition that the protocol is not working and is harmful to Northern Ireland. Those problems must be addressed.
“We wait to hear what the prime minister has to say but we will not make judgments based on words. It is decisive action that must be taken.
“Until that action is taken, the consensus necessary for power sharing in Northern Ireland does not exist.
“We respect the mandate received by other parties, but equally they must recognise the clear view expressed by the Unionist electorate.”