PM launches Anzac Day event in Sydney

Prime Minister Tony Abbott has paid tribute to Australia's military forces at the launch of a Sydney Anzac Day event aimed at raising money for war veterans.

Mr Abbott was in Manly on Saturday to help launch the Anzac Day Challenge, a running and trekking endurance event scheduled to take place on Anzac Day.

The race covers 100km of trails through Sydney's Ku-ring-gai and Garigal National Parks and raises money for various veteran charities.

Mr Abbott said as a prime minister who had put "our military personnel in harms way" it was incumbent on him to "pay tribute to all who have served our country in the military for more than 100 years".

"This Anzac Day challenge is a marvellous way for more of us to share their exertions if not their dangers," he added.

Mr Abbott said the event was an opportunity for ordinary Australians to "show solidarity" with those who had served in conflict zones.

The low-key appearance by the prime minister comes after he sacked Liberal Party elder Philip Ruddock as government chief whip on Friday.

Mr Ruddock has been replaced by his deputy, Queensland MP Scott Buchholz, with the move reportedly sparking a fresh round of bickering in coalition ranks.