The pilot of a recreational aircraft that went missing between Mount Beauty and Corryong in Victoria's high country is in "grave and imminent danger", according to authorities.

The Jabiru plane had one person on board, who last made contact at 12:41pm on Sunday afternoon.

The search area has been refined to an area between Mount Beauty and Corryong.

The aerial search coordinated by the Australian Maritime Safety Authority had to be called off overnight due to poor weather and low visibility.

AMSA response duty manager Dan Gillis says the difficult search conditions and time passed since the pilot went missing are of serious concern.

"We've got what we call a distress phase, we're concerned the pilot is in grave and imminent danger.

AMSA sent two helicopters and a fixed-wing rescue aircraft from Melbourne to search the area yesterday, and this morning additional rescue helicopters are on stand-by to continue the search once conditions improve.

"Our rescue aircraft is overhead monitoring weather in real-time," Mr Gillis said.

Police rescue units are on the ground searching trails in the area.

"It's extremely challenging in that area," Mr Gillis said.

"Searching on the ground away from the main trails and fire access routes is extremely difficult, and searching from the air even in good weather conditions is quite challenging due to the dense vegetation and mountainous terrain.

AMSA is conducting the aerial search, while the Joint Rescue Coordination Centre manages at least six teams of police and volunteer units searching on land.

"We're also working on mobile phone tracing and any other sighting reports that we can get from the public to try to refine the search area," Mr Gillis said.

"The smaller we can make the search area the better our chances are of locating the aircraft."