​Former NSW Labor boss Jamie Clements has been fined $4000 and convicted of unlawfully accessing the electoral roll after he sought confidential details about a voter for a union boss.

Clements, the former general secretary of the NSW ALP, was found guilty in May of using enrolment information without a permitted purpose.

The case laid bare the dysfunctional dynamics of state Labor's head office in Sussex Street as a key prosecution witness was accused of "waging a war" against Clements.

Defence barrister Phillip Boulten, SC, told the Local Court on Monday Clements was "no longer an active participant in ALP politics or any form of politics".