Police did not know what supplies the men had with them or their specific location.
"There's no huts up where they are," Mr Swanson said.
Authorities have received no direct contact from the three men and it is unclear what communications devices the climbers had.
"We don't know about cellphones. They didn't have an emergency locator beacon with them," Mr Swanson said.
Dr Bishop was an experienced mountaineer who had previously climbed in the Aoraki-Mt Cook National Park, Mr Swanson said.
Raphael Viellehner had previously climbed in Europe and Russia and was described as experienced, he said.
All men were described as extremely fit.
Police have contacted the families of all three climbers.
The trio left Plateau Hut at 1.30am on Monday morning, to climb via the Linda Glacier route. A guide last saw them at 4am at Teichlemann's Corner on Linda Glacier.
They were due back on Monday afternoon.
The guide told police conditions for climbing on Monday were reasonably good, but crevasses were an issue, with quite high freezing levels and unstable snow bridges.
Police said the three men were roped together when they left the hut.
The Department of Conservation Alpine Rescue Team conducted an aerial search early yesterday morning but the bad weather thwarted the team, who found no sign of the three men.
Mr Swanson said other climbers and visitors in the area would be "hunkered down in huts" for the next two days.
A guide was providing authorities with updates on weather and visibility, and would report any sightings of the missing party.
