Tony Abbott is likely to hold the West Australian seat of Canning in next weekend's byelection, yet is destined to face a challenge for his own seat as Prime Minister regardless.

Today's Fairfax-Ipsos poll shows that the voters of Canning are set to deliver up to a 10 per cent swing against the government, not enough to overwhelm the Coalition's margin in the seat of 11.8 per cent.

But a rebuke of this magnitude would be more than double the average postwar swing against a sitting government of 4 per cent, and three times the average postwar swing against a Coalition government of 3.3 per cent.