Matthew Christopher Williams was last seen at his Blackwood home on McLennan Street around 11am yesterday morning when he left to go prospecting in the forest surrounding Blackwood.

Up to 40 people from Victoria Police, SES, Department of Environment and Primary Industries and Parks Victoria are involved in a "significant" search for the man which continued on Monday.

He was expected to return home for a family function by 1.30pm, but has not been seen since.

It is believed the 37-year-old left the property, in a red Toyota 4Runner Surf twin cab utility with registration FNK 642.

Mr William's ute has a distinctive 'Destroyer 666' sticker on the rear window.

The alarm was raised after he failed to return for a family function and emergency services conducted a search until midnight on Sunday before resuming on Monday morning.

The Victoria Police airwing and motorbike units have been called in to assist with the search.

Moorabool Police Acting Inspector Jim Lappin said Mr Williams is believed to be an experienced prospector who knows the area well and there were no concerns for the man's health when he left home.

Investigators have released an image of Mr Williams in the hope that someone may recognise him and provide information on his current whereabouts.

He is caucasian in appearance with long brown greying hair, possibly in a pony tail and a short goatee beard.

Matthew is of medium build, has a 'pot belly', blue eyes and is 179cm tall.

He was last seen wearing a white T-shirt, either black jeans or shorts, blundstone elastic work boots and had a modern blue metal detector.

Matthew has a faded tattoo on one leg and both upper arms.

Police and family have concerns for Matthew as his disappearance is out of character.

The Blackwood area backs onto the Lerderderg State Park and is heavily wooded, rugged terrain.

It is popular among bushwalkers and trail-bike riders.

Anyone who sees Mr Williams or who can provide information on his whereabouts is urged to contact Triple Zero (000) immediately.

david.jeans@fairfaxmedia.com.au