The Australian Christians party says it will "reward" Liberal candidate Andrew Hastie for opposing same-sex marriage by preferencing him first in the Canning by-election.

Mr Hastie, an Anglican, has expressed his support for the traditional definition of marriage, and has also backed a "popular" vote so the issue can be decided by the Australian people and not the "political elite".

Australian Christians candidate Jamie Van Burgel said the party directed its first preference to Family First last time, but has chosen to reward Mr Hastie this time for having the courage to express his views.

"I think people are scared to go on the record to say whether they support traditional marriage or not and that's why we really support Andrew Hastie, because he hasn't been scared to broach the issue," Mr van Burgel said.

"100 per cent, we want to reward the Liberal or the Labor candidate if they have a strong view, and a correct and conservative view on traditional marriage."

"Andrew Hastie is obviously on the conservative side of politics. I don't think we should be scared to have an alternative view no matter how strong the so-called gay lobby is."

Mr Hastie's main opponent, Labor's Matt Keogh, has publicly supported same-sex marriage.

Australian Christians Canning by-election candidate Jamie van Burgel. ( Supplied: Jamie van Burgel )

The group Australian Marriage Equality (AME) has vowed to step up its lobbying efforts for the duration of the by-election.

AME WA Convener Brian Greig said the group had surveyed the views of all 12 candidates and would publish the results in local papers in the coming days, so that voters are fully informed.

He said AME was also planning to have a presence on voting day.

Mr Greig said Mr Hastie was entitled to his religious views, but accused him of failing to answer the critical question of what he would do as an MP if a "popular" vote endorsed change.

"The critical question really is, how would you vote when confronted with legislation?" Mr Greig said.

"It's all very well to talk in theoretical terms about a people's vote, but when that's all done and dusted, if there's to be actual legislation in the Parliament, how would you vote?

"And to my mind Andrew Hastie has not been fully clear on that as yet."

Canning voters conservative

Voting patterns in Canning highlight the conservative nature of the electorate.

At the 1999 referendum, 67 per cent of Canning electors voted against Australia becoming a republic.

Meanwhile at the 2013 federal election, Australian Christians secured 3.1 per cent of the vote in Canning, compared with about 1 per cent nationally.

A recent ReachTel poll of 782 people in Canning said there was 46.9 per cent support for same sex marriage, and 40.8 per cent opposition.

National polls have put support for same sex marriage at about 60 per cent or higher.

The Canning by-election is on Saturday, September 19.

Labor's Matt Keogh campaigns in Henderson

Mr Keogh today campaigned outside Canning, at the Australian Marine Complex in Henderson, which is in the electorate of Fremantle.

Accompanied by Labor spokesman for employment, skills and training Brendan O'Connor, Mr Keogh said the complex needed to be further expanded as a jobs hub for the whole region.

Mr Keogh also criticised the Abbott Government for not committing to further defence shipbuilding in Western Australia.

He said investment in skills training and jobs at the Australian Marine Complex were critical.

"It is, and has to be, a critical jobs centre for the whole south metropolitan Peel region of Perth," he said.

"And that's a clear jobs centre also for the people of Canning. You know, Armadale, Mandurah, this is going to be, and is, a critical jobs hub."

Mr Hastie today campaigned in Armadale, Kelmscott and Roleystone, meeting community groups and doorknocking.

Crikey election analyst William Bowe told the Perth ABC mornings program the Liberals were doing a good job focusing public attention on Mr Hastie rather than the Abbott Government.

A Newspoll released today put Labor ahead 54 per cent to the Coalition's 46 per cent on a two-party preferred basis if an election was held today.

Mr Bowe said the more voters in Canning heard about Mr Hastie, a former SAS officer, the less the by-election would be focused on the performance of Prime Minister Tony Abbott and his Government.

"That is, in a nutshell, what has surprised me, the degree to which the Liberal Party have been able to make it about [Mr Hastie]," he said.

"He has got a very forceful image and I think there's a good integrated campaign by the Liberal Party to emphasise that point and hopefully, for the Liberals' perspective, to make people vote on the basis of anything other than the way they feel about the Government in Canberra, which is overwhelmingly hostile."

Voting in the by-election started today with FIFO workers and travellers able to cast their ballot ahead of the poll on September 19.

The Australian Electoral Commission is providing the service during selected hours during Monday to Friday this week and next week.