The search for a missing tramper in Milford Sound will resume today.

British man Eli Sweeting failed to return from a day trip to climb Mitre Peak on Sunday.

The search was called off on Thursday due to bad weather, but police said their efforts would resume on Friday, with fine conditions forecast.

In a social media post, his sister Serena Sweeting expressed her thanks to search crews on behalf of worried family and friends.

"The rest of the family are located in England and this is an incredibly worrying time. Thank you so, so much to everyone out there looking for Eli. I feel so hopeless being so far away but it's reassuring the effort going In to find him. If anyone spoke to him please reach out to the police with information."

Heavy rain and strong winds hit the area on Thursday afternoon.

On Wednesday, search helicopters were unable to take to the air in bad weather but ground searches had continued.

Police said about 60 volunteers, 10 police staff and helicopter and tourism staff were involved on Tuesday.

Surf Life Saving said personnel from Otago and Southland would join the search when it resumed. The six-member team was to search the shoreline and water with inflatable rescue boats and a jetski.