Family members have joined the army in the search for two men lost in the bush south of Taupo.

One of the missing men has been named as Vincent  Taurima from Palmerston North.

Vincent's uncle, Hadleigh Balloch​, said his nephew didn't have much experience in the bush - but he still had hope.

"Vinnie's a soldier," Balloch said.

"I think I'll make it out alive. I hope, anyway."

Vincent is one of two men who have been lost in the Tongariro National Park bush since Saturday.

They ran into the bush after ditching their car after being pursued by police on the Desert Road.

They rang 111 for help on Sunday after becoming lost and have not been seen since.

Army personnel from Waiouru Army Base joined the Land Search and Rescue volunteers on Wednesday – the fourth day of the search.

The discovery of a plastic water bottle and shoes on Tuesday – which may have belonged to the pair – helped police to focus on a particular area.

The search is now concentrated in a three-square-kilometre area, close to the Pillars of Hercules gorge.

The gorge is part of a walking track to the DoC's Urchin campground.

Tuesday's discovery of items possibly belonging to the pair – including a plastic water bottle and shoes – helped police to focus on a particular area.

However, officer in charge of the search, Inspector Kevin Taylor said, as more time passed, hopes of finding the men alive were fading.

Due to the weather, a helicopter is unable to join Wednesday's search.

Balloch​ said Vincent was not trained in bushcraft.

"He doesn't know anything about the bush. He just knows how to beat around the bush."

Balloch said he would be joining the search soon.

"We've got the bulldog here to help sniff him out."​

Vincent's father, Tony Taurima, told Newshub his whanau was devastated by the boys' disappearance, but they were holding on to hope he and his friend will be found alive.

"I just want him out of there, that's all I want. I don't care what it takes," Taurima said.

"He's still a kid in my eyes… He's still my boy."

Vincent's brother, Taurus Taurima, told Newshub he was joining the search.

"We were told we weren't allowed to go in, but, we were in there anyway.

"We're here. We're doing out best to make sure we find him and bring him home," Taurus said.

Vincent's friend is believed to have a gash to his head and last time contact was made, he was unconscious.

Anyone in the area is asked to contact police immediately if they see, or have seen, two men on the Desert Rd or in the Kaimanawa Forest area.