"We are continuing to check whether candidates declared to our agency have parliamentary eligibility. We have decided that Necmettin Erbakan, Orhan Dogan, Selim Sadak and Hatip Dicle cannot become members of parliament," Muammer Aydin, the head of the Electoral Board (YSK), said.

Erbakan, 80, served as Turkey's first Islamist prime minister for one tumultuous year until June 1997 when the army, guardians of this Muslim-majority country's strictly secular system, forced him to resign.

In January 1998, the constitutional court outlawed his Welfare Party for undermining the secular order and banned him from politics for five years.

He was later sentenced to two years and four months for embezzling party funds, but escaped jail time thanks to a law that allows convicts over 75 to serve their sentences at home.

Erbakan had been planning to run in the July 22 election as a candidate from the small Islamist Felicity Party (SP).

Dogan, Sadak and Dicle are former Kurdish lawmakers who have been convicted, along with human rights award winner Leyla Zana, for having links with separatist Kurdish rebels.

The four entered parliament in 1991 on the ticket of a social democratic party but lost their seats three years later for collaborating with the Kurdistan Workers' Party (PKK), an outlawed group fighting for Kurdish self-rule since 1984.

They spent 10 years in jail for collaborating with the rebels before being released in June 2004.

The three were among independent candidates fielded by the main Kurdish political movement in Turkey, the Democratic Society Party (DTP), while Zana chose not to stand for election.

The DTP withdrew from the elections and decided instead to field independent candidates in a bid to bypass the 10 percent national threshold needed for parties to be represented in parliament.

Many Kurds have become legislators in Turkey as members of mainstream parties, but pro-Kurdish movements have failed to overcome the 10 percent limit although they usually dominate the vote in the country's mainly Kurdish southeast and routinely win local elections.