Former Prime Minister Tony Abbott has faced off against newcomer Zali Steggall in Warringah debate.

Former prime minister Tony Abbott has described the lead-up to the election as “very ugly” after a volunteer for his campaign was allegedly stabbed last night.

Police said the 32-year-old man was stabbed in the stomach with what was believed to be a corkscrew while putting up posters of the member for Warringah at Balgowlah Heights Public School, on Sydney’s northern beaches, about 8.30pm.

While plastering posters the man and other volunteers were yelled at by another man who was walking by, The Daily Telegraph reported.

The two men got into an argument before the 32-year-old was stabbed with what is thought to be a screwdriver.

Police said a 62-year-old man was charged with two counts of common assault and will face Manly Local Court on June 5.

The victim was not believed to be badly injured.

Mr Abbott is facing a major challenge from independent Zali Steggall for the seat he has held for 25 years in today’s election.

He told reporters this morning it had been a “very ugly” campaign with a “lot of low blows”, AAP reported.

“Lucky he wasn’t seriously hurt,” the former Liberal leader said of the stabbed volunteer.

“He’s back at his post today.”

Ms Steggall said the incident was “appalling” but doesn’t believe the alleged culprit was linked to her campaign.

“We have checked and I don’t (believe) that they are. I would be extremely shocked and extremely disappointed (if they were),” she told reporters.

“We should be respecting everybody and that’s just an appalling incident.”

Mr Abbott holds Warringah with an 11 per cent margin and many would have thought this was unassailable — that was until independent Kerryn Phelps secured a shock win in the blue-ribbon seat of Wentworth, which retiring Liberal MP Malcolm Turnbull had held with a 17 per cent margin.

Now Mr Abbott is in what he has described as the “fight of my life” to hang on to his seat and political career.

Internal Liberal Party polling done in the electorate ahead of the election being called was reportedly “diabolically bad” for Mr Abbott.