A SEARCH has resumed this morning for a man who went missing after going for a swim with a friend in Victoria's north last night.

The 20-year-old man was swimming in the Goulburn River at Seymour, about 100 kilometres north of Melbourne, when he got into trouble and disappeared under water at about 7pm last night.

His 21-year-old friend managed to swim to shore and notify emergency services.

A team involving Victoria Police, State Emergency Services and the Country Fire Service are searching for the missing man. Search and Rescue Police were expected to join the search this morning.