Extending negotiations to restore power-sharing in Northern Ireland would be pointless, Sinn Féin has said.

Party negotiator Conor Murphy said what was needed was political will to get a deal over the line, not extra time.

Mr Murphy said if no agreement emerged by next Monday's deadline then Northern Secretary Julian Smith should push ahead and call an Assembly election.

Mr Smith flew to London today to update British Prime Minister Boris Johnson on the state of negotiations to resurrect the defunct institutions, three years after their collapse.

Back in Belfast, there were reports of angry exchanges during a meeting of the main party leaders this morning. One source described it as a "shouting match".

The process is continuing in a week that will witness two further strikes by workers in Northern Ireland's crisis-hit health service.

Parties are at odds over proposed legislative protections for Irish language speakers and reform of a contentious Stormont veto mechanism called the petition of concern.

Politicians are also trying to agree changes to Assembly rule to make it less susceptible to implosion in the future.

The Irish and British governments are anticipated to table the outline of a deal later this week, and urge the five main parties to sign up to it.

Mr Murphy rejected the suggestion that giving politicians more time would make a difference.

"We have been at this for three years, when is enough time enough time?" he said.

"We don't need dramatics, we don't need grandstanding - what we need is political will to get an agreement.

"The issues have been rehearsed and well-rehearsed for a long time now."

Mr Murphy also moved to downplay the significance of the apparent bad-tempered exchanges during the leaders' meeting.

"You get good days and days when people are a little more tetchy, I wouldn't get overly worried about it," he said.

"What's important is what comes out at the end of this process, not about what happens at every junction throughout it."

If a deal is not reached by the 13 January deadline, legislation to give civil servants additional powers to run Northern Ireland's struggling public services expires and Mr Smith will assume a legal obligation to call a snap poll.

Sinn Féin was the only one of the five main Stormont parties to hold a press conference on the state of the talks today.

Mr Murphy again singled out the DUP as the party he claimed was holding up progress.

Earlier, Traditional Unionist Voice leader Jim Allister, who is not involved in the talks, said there was absolutely no need, requirement or justification for an Irish language act.

He claimed the sector was already "over-feted", pointing to the education of children in Irish.

He said: "It wants more, more, more. Why?

"Because the whole agenda of an Irish language act has nothing to do with linguistics, it has everything to do with politics, and the politics of a weaponised demand for an Irish language act is about de-Britishising Northern Ireland, making it a more uncomfortable place for unionists in their own land.

"I am very clear, therefore, no unionist should be conceding anything in that regard."