It could be due to sheer voter fatigue, but a high number of West Australians have been convicted and fined for not voting in the Senate election re-run last year, their third election in less than 18 months.

Australian Electoral Commission (AEC) state manager Marie Neilson said 964 non-voters had convictions recorded in the magistrates court this year, after failing to provide the AEC with a valid reason for not voting in the April 2014 poll.

That is compared with 354 cases of non-voting in the 2013 Federal election, held in September.

"It was a high number because of the low turnout in the Senate election," Ms Neilson said.

She said fines for not voting ranged from $20 to $170, with religious objections among the valid reasons for which people could be excused from the compulsory voting system.

Last year's election was the second time West Australians had voted for their Senate, and also came after the March 2013 state election.

The High Court, sitting as the Court of Disputed Returns, overturned the first Senate results after 1370 ballot papers went missing, ordering a new election.

Only 88.5 per cent of eligible voters took part in the new election, compared with 92.1 per cent in the previous poll.

"About 92 to 95 per cent is the general turnout for an election," Ms Neilson said.