A Sydney mechanic says the campaign in former prime minister Tony Abbott's seat of Warringah has become increasingly nasty, after his "Vote Tony Out" banner was repeatedly vandalised.

Key points: A mechanic in North Manly says he has had to repair his 'Vote Tony Out' poster four times

A mechanic in North Manly says he has had to repair his 'Vote Tony Out' poster four times He installed a security camera after the first incident but that was later stolen

He installed a security camera after the first incident but that was later stolen The seat of Warringah is set to be a tight contest between former prime minister Tony Abbott and independent Zali Steggall

Aaron King said the banner, which hangs outside his business on North Manly's busy Pittwater Road, has been painted over and slashed on four separate occasions.

"They're removing the word 'out' so it just says 'Vote Tony'," he said.

"It's really frustrating because it's costing me money and time.

"It's just opinion — I'm not saying anything rude or anything wrong."

During the most recent attack last Friday, Mr King said the vandals stole a security camera before slashing the banner and defacing a number of independent rival Zali Steggall's campaign signs.

"I put the camera up after the first incident," Mr King said.

"I didn't get any footage, so I think the person's climbed up ... removed it and then slashed the sign."

Aaron King tries to repair his banner after vandals leave their mark again. ( ABC News: Jessica Kidd )

With the election only four days away, Mr King feels as though the dirty tactics are escalating.

This vandalism comes less than two weeks after obscene caricatures of Mr Abbott emblazoned with expletives were found in Manly, Mosman and Seaforth.

NSW Police are investigating that incident and released footage of two men who they believe could "assist with inquiries".

Both Mr Abbott and Ms Steggall condemned vandalism of campaign material.

Mr King, who describes himself as long-time Liberal voter, became involved with the Vote Tony Out (VTO) campaign through Facebook, and later through his neighbour and VTO organiser Mark Kelly.

The mechanic suggested placing a banner outside his business where it would get plenty of attention from passing motorists.

He conceded he may lose some clients over the banner but said the majority of clients share his views about Mr Abbott.

Mr King has reported the incident to NSW Police and is awaiting a response.