"Today I have submitted to the Speaker of Parliament my resignation as a Deputy Speaker with the explanation that I no longer enjoy the political trust of the HDZ Presidency," Seks said, adding that he also proposed that his resignation be immediately added to the parliament's agenda.

Seks decided to step down after the HDZ Presidency on Tuesday evening decided to replace the current two HDZ deputy speakers of parliament, Jadranka Kosor and him, by two other HDZ members: Tomislav Culjak and academician Zeljko Reiner.

According to HDZ leader Tomislav Karamarko, the replacement of Kosor, his predecessor as HDZ president, and Seks was approved by all presidency members with two abstentions.

"I am disappointed because I do not see any correlation between my performance as Deputy Speaker of Parliament and the outcome of the intra-party elections," Seks said, ruling out his departure from the HDZ.

Kosor told the national broadcaster HTV's late night news programme on Tuesday that the decision on her replacement had been made by those whom she had enrolled in the party.

"I have worked well and with commitment. I brought accession negotiations with the European Union to a conclusion and fought against corruption," she told the HTV. She said that she had invested a lot of effort in the HDZ and would remain loyal to that party.