West Australian Liberals have brokered the deal with One Nation in a bid to win re-election at next month's state election.
Liberal how-to-vote cards will preference Senator Pauline Hanson's group above the Nationals, traditional Coalition allies, in regional upper-house electorates.
The Nationals and Labor call it a desperate move over poor polling, but senior Liberal MPs are defending it and suggesting the Liberal National Party might try the same in Queensland.
