The Australian Prime Minister, Scott Morrison, rejected claims on Sunday regarding how he launched his political career, accusing him of vilifying his rival over his Lebanese heritage and rumors he was Muslim. 

Morrison's party members signed legal declarations indicating that he advised them in 2007 that his opponent in a local election, Michael Towke, was too hazardous for the Liberals to support as their candidate.

The pair claimed that this was due to his ethnic background, after a "strong rumor" that the Lebanese Christian was Muslim, according to reports in The Saturday Paper. 

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"I could not reject this more fundamentally," Morrison told reporters Sunday, adding that close to an election people "make all sorts of things up because they have other motivations".

Morrison is poised to call an election in the coming days, hoping to capitalize on a recent budget, but he had little time to sell it before the controversy broke out.

The claims relate to his early political career when he was vying for the Sydney seat of Cook, where white and Lebanese Australians brawled on a beach during the racially fraught Cronulla riots in 2005.

Towke told Nine newspapers on Sunday that among tactics used to unseat him from Cook in 2007, "racial vilification was front and center and (Morrison) was directly involved."

He publicly backed a 2016 account that preselectors informed him that Morrison had told them in 2007 “a candidate of Lebanese heritage could not hold the seat of Cook, especially after the Cronulla riots” and there was a “strong rumour” that Towke was a Muslim.

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The 15-year-old claims surfaced after Morrison's Liberal party colleague Concetta Fierravanti-Wells alluded to them in Parliament on Tuesday during a rare attack on the Prime Minister.

"In my public life, I have met ruthless people. Morrison tops the list," she said, adding that he "is not fit to be prime minister."

The reprimand from a member of his own party added to the pressure on Morrison, who needs to close a 10-point difference between his conservative government and the Labor opposition to retain power in the election, which is scheduled for mid-May.