Five top members of Turkey's far-right Nationalist Movement Party (MHP) resigned on Saturday, plunging into chaos its preparations for a parliamentary election next month.

It was the second wave of resignations from the party ahead of the June 12 election, in which the MHP's prospects of exceeding the 10 percent threshold needed to retain their place in parliament were unclear.

Prime Minister Tayyip Erdogan's ruling AK Party is expected to secure a third consecutive victory in the election, with opinion polls putting its level of support at around 45 percent.

The MHP resignations was triggered by the broadcast on a website of secretly filmed videos which showed senior members of the party in romantic trysts and making politically compromising statements.

The latest resignations brought to nine the number of senior MHP party members to resign over the video scandal.

The website, named "Different Idealists", had threatened to broadcast further compromising video recordings if party leader Devlet Bahceli did not resign by a deadline of May 18. He has not resigned.

It was not clear who was behind the website.

State-run Anatolian news agency said Deputy chairmen Osman Cakir, Umit Safak and Mehmet Ekici, along with General Secretary Cihan Pacaci and his deputy Mehmet Taytak resigned their party membership and candidacies to be members of parliament.