Michael Keenan’s decision to quit politics on the cusp of the Federal election could hand Labor the key seat for the first time in 15 years, with a poll showing Labor pulling ahead after his shock resignation.

As the Liberal Party factions wrangle over a potential successor to the long-serving minister, internal Labor polling suggests his decision means Prime Minister Scott Morrison faces another major headache in WA.

The poll of 950 voters, taken after The Weekend West broke the story of Mr Keenan’s departure last Saturday, shows Labor is running neck-and-neck with its rivals on primary votes, at about 36 per cent each, with only 6.8 per cent of people polled undecided.

That could translate to a Labor win by as much as 1.5 per cent after the distribution of preferences.

Mr Keenan carried the seat with a 49.5 per cent primary vote at the 2016 election, according to AEC records.

Camera Icon Michael Keenan wants to spend more time with his wife Georgina and their four children, Rupert, six months, Hugo, three, Theo, six and William, seven. Credit: Nic Ellis

Labor has been claiming Stirling as a potential gain for much of the last year, suggestions previously dismissed by senior WA Liberals.

It suggests as many as 20 per cent of people polled who voted for Mr Keenan in 2016 are more likely to shift their vote to Labor in the wake of his departure.

It also marks health — traditionally a Labor strength — as the biggest issue for Liberal-leaning voters, with employment growth the top issue for Labor voters.

Mr Keenan said he was confident the Liberals could win Stirling, especially as voters wake up to the dangers of a Shorten government. “They know Bill Shorten fought us all the way on our GST reforms that will deliver an extra $4.7 billion for WA’s economy,” he said.

“They know that he wants to steal their hard-earned retirement savings. His tax on housing will slash the value of your family home. And his $200 billion worth of extra taxes will be like a wrecking ball through the Australian economy.”

Labor polling also suggests Julie Bishop’s much-speculated departure from Curtin would have little impact on the party’s chances.