Western Australia's three-month shark cull trial earlier this year is expected to cost $1 million, Premier Colin Barnett has revealed.

The trial between January and April involved baited drum lines being set off beaches in Perth and the South West.

The policy was brought in after a spate of fatal shark attacks in WA, attributed mostly to great whites.

Earlier this year, it was revealed the Government was paying a private contractor more than $610,000 to set and monitor lines in the South West during the trial period.

The Department of Fisheries was responsible for the policy in the metropolitan area.

The Premier today told a budget estimates hearing the exact details of the programme would be released next month.

"The costs are in line with what was anticipated," he said.

"That's the actual, if you like, the catching of sharks part of it, that will probably come out a little over $1 million - in line with expectations."

A total of 172 sharks were caught during the trial, including 50 tiger sharks larger than three metres, but no great whites.

The Government is seeking federal approval to extend the policy for another three summers.

It has claimed the shark cull was a great success but there has been community opposition to the policy with a number of large public rallies being held.

Earlier this year environmental campaign group Sea Shepherd failed to get a Supreme Court order to stop the cull.

It had argued the catch-and-kill policy had been improperly introduced, but the court ruled the introduction of the drum lines was valid.