The man failed to return after a planned day trip to climb Mitre Peak, sparking a search and rescue operation shortly before midnight on Monday.
Detective Tracy Ward yesterday said a large number of resources had been working through arduous terrain, assisted by helicopter crews.
In an update this morning police said that the search was resuming but weather conditions meant helicopters were now unable to fly.
"However, teams on the ground will continue to search from first light."
Rain is forecast for today and an orange level heavy rain warning for Fiordland comes into force from 10pm.
Det Ward said yesterday they were looking at "a wide search area in a very rugged part of New Zealand".
While teams were yet to find any items that could help narrow the search area, Det Ward said they were remaining positive.
"The man we are looking for is experienced in the outdoors and we believe he had suitable clothing and provisions, which can make all the difference," Det said.
"We are in contact with his next of kin, but at this stage are not in a position to release further details about him."
-APL
