They had no option but to follow the attackers' route back along the only path out to safety to seek help after the attack.
The 55-year-old Mackay, Queensland, businessman, told media in Cairns yesterday how he watched in horror as two porters were hacked to death with bush knives after he was struck.
"We'd just set up camp, it was raining, it had just started to rain and some of us were just beside the tents.
"Then there was a whole lot of noise, shouting, and I thought the boys had found ... an animal or something like that.
"The next thing I thought, what's going on.
"I started to put my head out the tent and then smack.
"The blood just erupted out of my head, I look up and I see this guy with a mask on standing over me and then the whole thing just unfolded.
"They were laying into the porter boys ... I realised they were actually butchering the porters, it was just appalling to be honest and we're very, very fortunate."
Mr Bennett told media he thought he had been shot before he realised he had been clubbed on the head with a rifle butt.
He told fellow trekkers to lie low and watched as the attackers reigned blows on two porters.
"I saw them taking to the porters with bush knives ... one appeared to be in control.
"They attacked again and again."
Mr Bennett, a former Rotorua Boys' High School student, talked briefly to the Rotorua Daily Post from Cairns.
After growing up in the Ford Block he left school to join the police and was posted to the Diplomatic Protection Squad for four years.
Described as "adventurous" by Rotorua family friend, Geoffrey Ballantyne, Mr Bennett had spent the past year getting fit enough to walk the 61km trail.
Mr Bennett was met at Port Moresby by the New Zealand High Commission before he flew on to Cairns.
PNG Trekking Adventures, which organised the trek, reported all the group's valuables and possessions had been stolen.
Papua New Guinea Prime Minster Peter O'Neill had called for the death penalty for the attackers when caught.
Police condemned the violent attack and issued a stern warning to the culprits.