Searchers looking for two missing Australian yachtsman will again battle high seas as they attempt to reach an island to the north of Tonga.

The men, who are aged in their 60s, have been missing since Thursday night when they called a relative in Victoria to say their yacht had run aground and was breaking up.

A search of the island of Late was delayed yesterday when authorities could not find a boat to transport the search party.

It was then abandoned due to rough seas.

Another attempt will be made today but authorities are again expecting three-metre swells in the area.

Maritime New Zealand's search and rescue mission coordinator John Dickson says getting to the island is a challenge.

"The island is a volcanic island and you can only approach it by a small dinghy because it's surrounded by a lot of rocks," he said.

"Once you get to the island, you then have to scale a cliff to get up onto the land and the island itself is covered by very, very dense bush and you have to use a machete to get through."

The names of the men have not been released.

Victorian police are coordinating contact with the pair's next of kin.