Prime Minister Mesut Yilmaz is accused of entertaining ties with the mafia and tampering with the $600m sale of a state bank - charges he has denied.

Correspondent Chris Morris: Opposition has more than enough votes to bring down government

Mr Yilmaz has acknowledged that defeat in Wednesday's vote is inevitable, now that a key partner in the coalition has withdrawn its support.

If he loses, he must hand over his resignation to President Suleyman Demirel.

It is expected that President Demirel will then appoint an interim government to manage the elections, scheduled for next April.

He is also likely to ask Mr Yilmaz to stay on in a caretaker capacity, in the absence of any obvious alternative.

Call for new elections

Mr Yilmaz has called for elections to be held even sooner than April 1999, when they were set by parliament.

"What must be done next is to go for elections as soon as possible," he said on Tuesday.

He was speaking at a time of high national sentiment, amid a fierce row with Italy over the future of Kurdish rebel leader Abdullah Ocalan.

But he ruled out any prospect of a new coalition with his rival, former Prime Minister Tansu Ciller.

Mr Yilmaz came to power nearly 17 months ago after Turkey's first pro-Islamic government was forced out of power by the military.

Turkey's secular parties, though deeply divided themselves, are anxious to prevent the Muslim party, Virtue, returning to power.