Boris Johnson has told the DUP to “roll up their sleeves” and enter government at Stormont with Sinn Fein.
The prime minister also defended government plans to introduce a new law allowing them to unilaterally rip up the Northern Ireland Protocol.
Johnson spoke out after talks with the leadership of all five parties in the Northern Ireland Assembly.
The DUP has refused to agree a power-sharing deal with Sinn Fein - who are now the largest party at Stormont - unless the Protocol governing trade between Britain and Northern Ireland is redrawn.
They are angry that it has led to a customs border in the Irish Sea and last week refused to nominate a speaker, meaning the Assembly is unable to function.
Asked if he had made efforts persuade the DUP to join a power-sharing executive, the PM said: “I think everybody should be rolling up their sleeves and get stuck in to the government of Northern Ireland.
“The province has got so much going for it but you need leadership and you need government.
“So you bet I said to the DUP in particular ‘we want to see you back in the executive, we want to see you nominating, we want to see a speaker in the assembly’, of course.
“The issue they have is that they object to the operation of the protocol. We don’t want to scrap it, but we think it can be fixed.”
Foreign secretary Liz Truss will tomorrow unveil legislation which would allow the government to unilaterally over-ride parts of the Protocol which ministers are opposed to.
Striking a conciliatory tone, Johnson said he believed it was possible for the UK and EU to agree reforms to the agreement which would make that unnecessary.
But he said the legislation was needed as “insurance” in case a deal could not be reached with Brussels.
He said: “None of the parties – I spoke to all five parties just now – not one of them likes the way it’s operating, they all think it can be reformed and improved – from Sinn Fein to SDLP, DUP, all of them.
“The question is how do you do that? We would love this to be done in a consensual way with our friends and partners, ironing out the problems, stopping some of these barriers east-west.
“But to get that done, to have the insurance, we need to proceed with a legislative solution as well.”
Speaking after his meeting with the prime minister, DUP leader Sir Jeffrey Donaldson said Johnson needed to back up his words with action.
He said: “The tabling of legislation is words. What I need is decisive action. And that means I want to see the government enacting legislation that will bring the solution that we need. But let’s see what the Government are prepared to do.”
Donaldson also hit out at Sinn Fein president Mary Lou McDonald, who had earlier claimed the PM’s priority was “placating the DUP”.
He said: “Sinn Fein need to stop this puerile nonsense that they’ve been engaging in of late, get serious and let’s deal with serious issues, instead of this silly approach that they take of attacking everybody who doesn’t agree with them.
“The Prime Minister has a duty to resolve these issues, that is why he is here.”