Northern Ireland's political future hangs in the balance as its quibbling parties look set to miss Thursday's deadline for forming a government, despite a huge cash incentive.

After three months of negotiations to put a power-sharing administration in place the squabbling was still going on just hours ahead of the 4:00 pm (1500 GMT) deadline.

If the parties cannot agree to form a semi-autonomous government in Belfast, Northern Ireland will likely be fully governed from London, although a last-ditch arrangement might yet be possible.

Britain's Northern Ireland Secretary James Brokenshire has said there would be "profound and serious implications" in missing the deadline.

The power-sharing Northern Ireland Assembly is a cornerstone of a peace process that ended three decades of violent conflict in the province, broadly split between Protestant British unionists and Catholic Irish nationalists.

The assembly has powers over matters such as health, education, justice and the province's economy.

Tensions between the two main parties boiled over in January and the Irish republican Sinn Fein pulled out of the executive.

That triggered a March 2 snap election in which the conservative Democratic Unionist Party (DUP) saw its lead over Sinn Fein slashed.

But the DUP is feeling emboldened since Monday when it agreed a deal in the British parliament with Prime Minister Theresa May's Conservative Party to prop up her minority government.

In return, the DUP secured an extra £1.0 billion ($1.3 billion, 1.1 billion euros) for Northern Ireland out of the UK coffers over the next two years.

However, without an executive in Belfast, it could be London ministers and civil servants who decide how the cash boost is spent.

- Wriggle room and influence -

The Belfast Telegraph, the province's biggest-selling newspaper, suggested Thursday that the UK parliament deal had switched the momentum from Sinn Fein to the equally-entrenched DUP.

"Sinn Fein has given itself little wriggle room," it said, while the DUP now "has the direct ear of the prime minister and, more importantly, influence".

DUP negotiator Edwin Poots said the party was happy to get an executive in place, then continue with talks on the sticking points.

"It is up to Sinn Fein if they wish to do that, or if they want to break through the deadline that is a matter for them, but we are happy to nominate ministers," he said.

A Sinn Fein source told AFP there had been no movement so far Thursday.

The major sticking point is Sinn Fein's demands for greater recognition of the Irish language, which the 2011 census found four percent in Northern Ireland could speak, read and write.

Sinn Fein's former education minister John O'Dowd urged London and Dublin to fizz up the talks in the final few hours.

"The DUP have not moved to address the issues of rights, equality and respect which caused the collapse of the assembly," he said.

"There is an onus on the two governments to inject the necessary urgency and momentum to bring this negotiation to a successful conclusion."