Arab pro-democracy uprisings spell more regional instability that could complicate peace efforts between Israel and the Palestinians but also make it necessary to get the process back on track, envoy Tony Blair said on Sunday.

Blair will sit down separately with Israeli and Palestinian officials this week in Jerusalem to try to revive a peace process that broke down more than a year ago because of a dispute over Jewish settlement expansion.

"It is a great thing that people are wanting democracy, but in the short term there is reduced stability in the region so that can pose problems for Israel and the peace process," said Blair.

"Because of the instability and uncertainty in the region, it's right that we grip the peace process and put it back on track again."

"We need strong, clear commitments that both parties will produce comprehensive proposals on borders and security within 90 days," he said.

Underlining the bleak prospects for a breakthrough, Israel recently unveiled plans for new settlement building including 2,600 homes on land near East Jerusalem, where the Palestinians aim to found their capital.

Mahmoud Abbas's Palestinian Authority refuses to hold direct talks with Israel until it stops building Jewish settlements on land the Palestinians want for a state.

"It's a problem, there is no doubt about that at all," said Blair, a former British prime minister who represents a Quartet of mediators made up of the United States, the European Union, Russia and the United Nations.

"There is a clear line of the Quartet statement about refraining from provocative actions and it's important that's adhered to," he told Reuters in an interview at a business forum by the Dead Sea in Jordan.

"You cannot expect people to go into a process then have unilateral actions that are going to disrupt it."

SEPARATE MEETINGS

By arranging separate meetings in Jerusalem, the Quartet failed to meet a goal set out in a Sept. 23 statement to bring the parties together for a "preparatory meeting" aimed at reviving the peace talks which broke down more than a year ago.

Blair denied the Quartet had lost credibility because of its failure to arrange direct talks, and played down the impact of tensions between the United States and Russia over how to deal with the Syrian government's crackdown on a popular uprising.

"When there is a disagreement of the international community and that is reflected in the Quartet, the Quartet is still easily the most practical and manageable way of making progress," he said.

A clear view was now emerging on Syria that President Bashar al-Assad, whose family has ruled Syria for four decades, appeared unwilling to allow a genuine programme of political reform, said Blair.

"That is why there are countries ramping up sanctions at the moment" he said.

Evolution was preferable to revolution, said Blair, because of the challenge of building a new system from scratch, but when leaders are not prepared to change, revolution is the only option.

Libya's Muammar Gaddafi remained defiant even after he was toppled in a violent rebellion, retreating to his home town and holding out for weeks until he was killed on Thursday.

Blair said he and other world leaders were right to have allowed Gaddafi to return from decades of diplomatic isolation because he had given up chemical and nuclear weapons programmes and cooperated in fighting terrorism.

"We were also equally right to condemn and then move to get rid of the regime when it turned its guns on its own people," said Blair.

"I said to Gaddafi at the outset of this: 'You've got a simple choice -- you either get out of the way and align with the people to engage in a process of change or if you try to hold onto power, in the end you will be removed.' And that is what happened."

Asked whether he regretted the move to rehabilitate Gaddafi in light of the bloodshed of the last eight months, he said: "These are tough judgments to make but if ... he still had a chemical weapons programme it would have been a lot tougher and a lot bloodier."