The desperate search for a man missing in bushland northeast of Melbourne will continue this weekend, as rescue efforts enter their sixth day.

The 62-year-old man from Croydon, identified only as Mark by police, was last seen at the Big River State Forest near Frenchman’s Creek campground off Big River Rd about 8.30am last Sunday.

Police said a camper had earlier spoken to Mark about 10.30pm on Saturday night, and said he was intending to walk to Woods Point the next morning.

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He was last seen wearing a light grey and dark blue jumper, white tracksuit pants, a blue zip-up jacket and black sneakers.

A search was undertaken of the area, with investigators locating a stripped duffle bag belonging to Mark between the Camp Track and Frenchman’s Spur Track during their search on Wednesday.

Police said searches for Mark will continue this weekend after a new witness said they may have passed Mark on Big River Rd between 8.40am and 8.50am the day he went missing.

Local police, Dog Squad, Solo Unit, Search and Rescue Squad, SES volunteers and the Wilderness Paramedics are all participating in the search.

“Police have serious concerns for Mark’s welfare due to the amount of time he has been missing,” police said.

“Investigators are also concerned given the cold weather in the area, and because Mark was not believed to be in possession of any camping gear at the time.

“Anyone who sights Mark or encountered him within the Big River State Forrest is urged to contact Triple Zero, and anyone with information is urged to contact Crime Stoppers.”

The Big River State Forest is a popular spot for camping, fishing, bush walking and mountain biking.

It is located about 3 hours northeast of Melbourne.