The conditions were believed to be low cloud with reduced visibility.
Hevilift had not released the names of the three men but said it had been in contact with their families.
New Zealand Defence Force PNG adviser Lieutenant Colonel Richard Taylor said many commercial helicopter operators were in the area, helping to set up the country's general elections.
"There're a lot of helicopters up there flying ballot boxes and election officials around."
The NZDF has three helicopters operating in the southwest of the country and the Australians have four, but they weren't involved in the search early yesterday, Taylor said.
"There are quite a number of commercial helicopters operating in that area so we're anticipating that some of those will be able to be used for searching for the wreckage, but to the best of my knowledge there's been no word received from the crash site that would indicate survivors."
Taylor said it would be a difficult search.
"It's quite rugged; you could probably describe it as a jungle version of the Southern Alps: very mountainous with a number of flat plateau areas scattered around where the population centres tend to be."
A former senior Hevilift employee said the company's base at Mt Hagen was a tight-knit community.
"It is a very hazardous area to fly in and the weather can bite you very easily, so safety is paramount," said the ex-worker, who declined to be named.
russell.blackstock@hos.co.nz