Centre-right Diko was holding party elections on Sunday in all districts to contest the positions of deputy chairman and three vice presidents.
The executive bureau members are also to be elected on Sunday, and members of the provincial committees.
Party leader Nicolas Papadopoulos remains in position as there were no challengers when he went to register.
Polls opened at 9am in all districts and some 33,000 party members were to vote. The results are expected around 6.30pm.
Papadopoulos went to vote at the Hilton Park Hotel in Nicosia around 10.30am.
He said the vote would herald a new era for the party, which experienced internal strife during the presidential elections this year, which Papadopoulos challenged and lost. In the aftermath, many party members left and others were expelled for not supporting Papadopoulos.