JERUSALEM, Oct 2, 2008 (AFP) - Israeli Prime Minister Ehud Olmert was questioned by police on Thursday for the eighth time since May on corruption allegations that led him to resign from office last month.

Investigators questioned Olmert for around two hours on the 'Investment Centre affair,' police spokesman Micky Rosenfeld told AFP, adding that the outgoing prime minister was likely to be questioned again in the coming weeks.

The probe -- one of several concerning Olmert -- involves allegations that as trade minister he steered tens of millions of dollars worth of state funds towards a company owned by his former law partner Uri Messer.

It is one of several criminal investigations into Olmert, who resigned on September 21 to battle the charges amid a growing chorus of criticism from political allies and foes alike.

All the allegations concern his dealings as Jerusalem mayor and trade minister in the 13 years before he assumed the premiership in 2006.

He will continue to serve as interim prime minister until Foreign Minister Tzipi Livni forms a new governing coalition or the country holds snap elections -- a period of political limbo that could last weeks or months.

Police have recommended that the 63-year-old Olmert be indicted on criminal charges in two cases where he is accused of illegally accepting large sums of cash from a US financier and multiple-billing foreign trips.

Olmert has denied any wrongdoing.

On Thursday, police again quizzed Olmert about the second of the two cases -- dubbed the Rishon Tours affair after the company that organised his travel -- and he refused to answer their questions.

His adviser Amir Dan said the acting premier had refused because police had already announced two weeks ago that they had completed their investigation of the case and had recommended that charges be pressed.

'At the start (of the interview), suprisingly he was asked about the Rishon Tours case,' Dan told army radio.

'Suddenly the investigators have remembered that they failed to check everything out,' he complained.

Olmert's resignation has dealt a major blow to already sluggish US-backed Israeli-Palestinian peace talks relaunched in November 2007, when the two sides vowed to try to reach a full peace deal by the end of 2008.

If Livni is unable to form a government in the coming weeks, general elections would be held early next year, which polls suggest would give the right-wing opposition Likud party the most seats in parliament.