Opposition groups made a surprise gain in Iraqi Kurdistan's weekend elections, but ruling parties feuding with Arab leaders in Baghdad clung to power and are unlikely to end a standoff threatening Iraq's fragile calm.

The preliminary results from Saturday's presidential and parliamentary polls came shortly after US Defense Secretary Robert Gates urged Kurdish leaders, in a visit to Iraq's largely autonomous Kurdish enclave, to act quickly to reduce tensions.

Gates met Masoud Barzani, re-elected as Kurdish president with 69.6 per cent of the vote, a former guerrilla leader who has refused to yield on claims to the oil-producing Kirkuk region.

That and related disputes may pose the chief threat to Iraq as sectarian violence ebbs since the 2003 US-led invasion.

Gates on Wednesday said Washington, where officials are increasingly worried about the rift between minority Kurds and majority Arabs triggering renewed violence, offered 'whatever assistance we can to help resolve these disputes in a peaceful manner', Pentagon press secretary Geoff Morrell told reporters.

The polls, the first time Iraqi Kurds elected a president directly, went off on Saturday without major disruptions.

Electoral officials said turnout was close to 80 per cent.

A reform-minded opposition movement, Change, took a surprise 23.8 per cent of the parliamentary vote, but complained of fraud and aggression from the region's ruling two-party alliance.

'These figures contradicted the real will of the Kurdish people and were the result of organised forgery ... by the two parties in power,' senior Change member Shamal Abdulla said.

An official from Iraq's national election commission said there had been eight serious complaints, but they were unlikely to affect the overall election results.

Barzani's Kurdistan Democratic Party (KDP) and Iraqi President Jalal Talabani's Patriotic Union of Kurdistan (KDP) took 57 per cent of the parliamentary vote.

'We are happy with these preliminary results and with the success of this election. It is a proud day for our people,' KDP official Jaafar Ibrahim said.

Maliki congratulates Barzani

There had been hopes that Iraqi and Kurd officials may be more ready to make concessions now that Kurdish electioneering, featuring fiery rhetoric about disputed land and oil, is over.

At a joint news conference, Barzani and Talabani said Iraqi Prime Minister Nuri al-Maliki would soon visit Kurdistan, and Talabani said they would 'tackle problems together'.

In what may be an olive branch between two leaders who barely speak, Maliki called Barzani to congratulate him on his poll win, state al-Iraqiya TV reported.

But Barzani said outstanding disputes could only be resolved by sticking to Iraq's constitution, which calls for a census and referendum in Kirkuk, a solution shunned by Baghdad and seen as as destabilising by the United Nations.

Political analyst and former Iraqi government spokesman Laith Kubba said, if anything, the Change list's success may spook the KDP-PUK alliance's into a more hardline stance.

'I think by instinct the PUK and KDP would play more on the Kirkuk issue, they will be much much harder in their approach, because (it can be used) for their political survival, to rouse national sentiment amongst the Kurds,' Kubba said.

Accompanying Gates in Arbil was General Ray Odierno, the top US commander in Iraq, who on Tuesday called the Kurd-Arab dispute the 'number one driver of instabilities' in the country.

Gates said yesterday (July 29) the clock was ticking for Kurds and Arabs to settle differences before US troops leave by 2012, a withdrawal that may be accelerated as security improves.

'I think there's at least some chance of a modest acceleration of the phased