There is the will to make devolution work in Northern Ireland, Prime Minister Tony Blair has said.
He was speaking as intensive multi-party talks aimed at brokering a deal to restore devolution began at St Andrews in Scotland.
He said progress had been made and it was time "to get the business done". "I believe the political will is there to do that," he said.
Mr Blair and Irish premier Bertie Ahern opened the three-day talks.
Mr Ahern said the two governments would try to find ways and compromises to deal with the "short enough list of outstanding issues".
DUP leader Ian Paisley said Sinn Fein must back policing and the IRA hand back any "ill-gotten gains" to enter government.
"We are not here to argue or debate with Sinn Fein we are here to listen - if they are going to deliver," he said.
Politicians were initially summoned to an opening round-table session.
Afterwards, during the evening, the parties will hold separate meetings with the two premiers. It is believed negotiations will be conducted on a twin-track basis
On Thursday for example the prime ministers are expected to concentrate on the topic of policing - other ministers will deal with issues related to the devolution of justice, parades, equality, human rights and changes to the Stormont rules.
On Friday, it is believed that the talks may deal with questions concerning the past and victims.
The negotiations are due to end at noon on Friday.
The UK and Irish governments have given the parties until 24 November to reach a deal on power-sharing, otherwise the assembly may be put into cold storage.
Mr Blair said the talks were a "one-off opportunity" to build a lasting future for the province.
Sinn Fein president Gerry Adams said he hoped the DUP leader was ready to "sort the issues out".
"The government's position... is very clear, that the working institutions should be in place by 24 November. That's Sinn Fein's position too," he said.
Ulster Unionist leader Sir Reg Empey said republicans must "grasp the nettle" of commitment to exclusively peaceful means.
"They must not make the mistake of bowling in short all the time, as they did over decommissioning," he said.
The SDLP's Sean Farren said the DUP should agree to a return to power sharing.
"Amendments have been proposed by, amongst others, the DUP - their amendments seem to us to be deliberately designed to inhibit not smooth the working of the agreement," he said.
Alliance leader David Ford said progress was needed to build solid and permanent devolution.
"The sectarian designation system in the Assembly must be scrapped immediately. Power must be shared not divided," he said.
In a departure for the talks, the Ulster Unionists were running their own blog on their website from the talks venue, giving a first hand account of what was going on.
The talks in Scotland come a week after the body monitoring paramilitary activity said the IRA had changed radically and some of its most important structures had been dismantled.
Mr Blair said at that time the IRA's campaign was over and there was a "unique opportunity" to reach a final settlement.
The focus is on Ian Paisley and Gerry Adams
The Northern Ireland Assembly was suspended on 14 October 2002 amid allegations of a republican spy ring at Stormont.
The court case that followed collapsed and one of those charged, Denis Donaldson, later admitted working as a British agent.
Direct rule from London was restored in October 2002 and has been in place since.
On 15 May this year, Northern Ireland's politicians took their seats in the Stormont assembly.
The government hoped recalling the politicians would help to pave the way towards a deal in the autumn.
A Preparation for Government Committee was set up to identify obstacles to the return of devolution. It met over the summer months.