CHARLOTTETOWN -- Stephen Harper's struggling Conservatives are employing the services of a controversial Australian campaign fixer who is credited with helping David Cameron confound the polls and secure a majority victory in last May's U.K. election.

Lynton Crosby has also been linked to tactics that have rallied voters fearful of immigration and crime behind the campaigns he advises.

A Conservative party source said Crosby has been giving advice -- primarily analyzing polling data -- since March. Another source said that Harper had met with Crosby in the summer, and the Australian told him then that his campaign strategy and preparation needed work.

Both sources spoke to The Canadian Press on condition of anonymity because they weren't authorized to publicly discuss internal party planning.

Campaign spokesperson Kory Teneycke refused to discuss campaign "staffing decisions" but confirmed Thursday that Crosby has been advising the party for a long time and is continuing to do so.

He denied suggestions that Crosby has taken over the campaign or was recruited in a bid to turn around the party's sliding fortunes at the mid-point of the race to the Oct. 19 vote. It was unclear whether Crosby is working from Canada or abroad.

Several Conservative sources have told The Canadian Press there is serious friction inside the party's war room, and widespread dissatisfaction with a perceived lack of nimbleness in the party's response to events -- particularly the Syrian refugee crisis.

Some of the blame has been focused on campaign manager Jenni Byrne, who had been travelling off and on with Harper.

Crosby has been dubbed the "wizard of Oz" for his role masterminding four consecutive election victories for former Australian prime minister John Howard in 1996, 98, 2001 and 2004.

The website for his firm, C/T Group, lists "strategic lessons of politics," which include how to "identify and focus on swing targets after establishing a base."

Harper long ago borrowed media-management strategies from the Australian government of former prime minister John Howard, as well as the idea of targeting portions of the population that together form a winning coalition.

Former Conservative marketing whiz Pat Muttart was said to have taken some of his cues from Australia during the 2006 election.

Crosby, meanwhile, also been described as "a master of the dark political arts."

The term "dog-whistle politics" is said to have originated in Australia in response to the tactics used by the Crosby-led Howard campaign team.

The term refers to the use of code words that seem benign to the general populace but which are intended to send veiled messages -- typically racist or otherwise distasteful messages -- to target voters.

During the 2001 campaign, Howard ministers falsely claimed that a ship full of would-be refugees had thrown children overboard in a ploy to secure asylum in Australia.

The false story played to the Howard campaign's hard line on migrants, with the slogan: "We will decide who comes to this country and the circumstances in which they come."

Crosby employed similar tactics in 2005 when he ran the unsuccessful Conservative campaign in the United Kingdom.

He is credited with creating the slogan "Are you thinking what we're thinking," which appeared on billboards, posters and campaign literature alongside messages on hot-button issues like, "It's not racist to impose limits on immigration," and, "How would you feel if a bloke on early release attacked your daughter?"

He successfully ran Conservative Boris Johnson's bid to become the mayor of London in 2008 and his re-election campaign in 2012.

Johnson has described Crosby as "the best campaign manager I've ever seen."