The climbers are stuck on the north western side of an outcrop, called the Lizard, near the summit, and have been communicating with police via text message.
Mike Parker, a pilot with the Taranaki Community Rescue Helicopter, said two attempts to fly to them today had failed due to high winds and low cloud.
"We've gone and had another look, conditions have definitely improved but it's pretty windy up there,'' he said.
"We were buffered around a lot and visibility at the top is still very cloudy.
"Unfortunately we weren't successful at this stage, so we'll wait for it to improve a bit more.''
Search and rescue teams set out this morning on foot to try to reach the stranded climbers. However, Mr Parker said he would like to reach the pair by helicopter to ensure they can be brought down tonight.
"Personally, fingers crossed for this evening, the forecast looks to be a bit better, and I would like to get this done before the sun goes down,'' he said.
A party of eight Taranaki police and search and rescue specialists came down off the mountain just before 4pm, to be replaced by a team of 12 rescuers from the Sir Edmund Hillary Outdoor Pursuits Centre (OPC).
The OPC people drove over from Turangi this afternoon after being on standby from 7am, and had heard that the two other climbers who descended safely had been at a lower altitude than the pair in the snow cave.
The forecast for the mountain promises better weather tomorrow.
The rescue team will not wait that long however if conditions improve this evening.
They said they were equipped to search at night, and would do so unless whiteout conditions persisted.
Fears are growing for the pair.
Mike Johns, from Taranaki Alpine Cliff Rescue which is involved in the rescue attempt, said they had "quite grave concerns'' for the stranded climbers.
"They've been stuck on the mountain now for nearly 24 hours, quite high up, so there are quite grave concerns for their wellbeing,'' he said.
"They didn't have overnight gear so they spent a pretty harsh night up on the mountain, and could have to spend another one on there as well.''
He said being stuck on Mt Taranaki for a second night would "diminish'' their chances of survival, because of how cold it is so close to the summit where the pair are believed to be sheltering in a snowcave.
They built the cave last night in a bid to protect themselves from the elements.
However, Peter Wilson, vice-president of the Federated Mountain Clubs of New Zealand, said the climbers should be safe in their shelter.
"If they're warm and dry, with warm and dry clothing, their chances are quite high,'' he said.
"Inside a snowcave the temperature will be around 0C to -1C, but it's definitely better than being outside.''
Mr Wilson said the pair had done the sensible thing by making the shelter, and that would help them survive.
"It looks like they did everything right by digging a snowcave and weathering the storm out. That's exactly the right thing to do,'' he said.
"It's uncomfortable, but they did the right thing.''
