The 34-year-old, nicknamed Pockets, has not been seen since about 9am on July 26.

A friend reported him missing about 10 days later.

He has not used his bank account or phone, leading to growing concerns for his welfare.

His mother, sister and ex-partner say they haven't lost hope.

“We do care about him and we don’t want to see anything bad happen,” ex-partner Jade Griffiths said.

“So just let us know that you’re OK.”

Police and SES volunteers ramped up their search on Thursday by scouring the Ovens and King rivers.

Officers have made other enquiries since he went missing which have not found any sign of the 34-year-old.

Mr Day, who lives an itinerant lifestyle, has been known to camp along the river at Wangaratta, near the train bridge.

Police found his tent a few weeks ago near the train line, but did not find anything inside to assist with their investigation.

His sister, Cherrona Chambers, said Mr Day’s drug and alcohol problems had been getting worse.

“Everywhere where we thought he might have gone has been checked and the police haven’t found anything,” she said.

“When he’s not on drugs and alcohol he’s a good person.

“But unfortunately his problems have got worse.”

Mr Day recently told a magistrate “it's been a bit of a rough trot lately", and that he sometimes started drinking as soon as he woke up.

He was urged to get help for his alcohol problem. 

Flyers seeking information, with two pictures of the missing man, have been put up around Wangaratta.

Mr Day is also known to frequent Benalla and could be in Melbourne.

Detective Sergeant Chris Hill said while police hoped to find him alive and well, “obviously we have significant concerns”.

“We don’t have any information to suggest all hope’s lost,” he said.

“We’re just keeping all options open.”

There is nothing to suggest foul play, but police also haven’t ruled it out.

The search, which had not unearthed anything by Thursday afternoon, may continue on Friday or at a later date. 

Detective Sergeant Hill said Mr Day had a tattoo of a name on his forearm, and tattoos of pockets on his thighs. 

He likely has a scruffy beard. 

“I love you … come back please,” his mother said on Thursday. 

Call (03) 5723 0888 or 1800 333 000 with information.