The family of a Hamilton man missing in Australia for nearly a month has doubled the reward for finding him.

Prabhdeep Srawn disappeared May 13 during a bushwalk in the Snowy Mountains southwest of the capital Canberra.

Police scaled back their search in late May due to poor weather, prompting Srawn's family to offer first $15,000, then $50,000 to anyone who "rescues or recovers" him.

Dr. Tej Sahota, whose wife is Srawn's cousin, says the reward has now been increased to $100,000.

The official search for the 25-year-old, who was a military reservist in Hamilton before moving to Australia, wound up last weekend.

Officials have said the chances of finding Srawn alive have decreased but his family has said it won't give up its efforts.

'Cold-weather training' offers hope

Wednesday will mark one month since Srawn went missing.

Srawn's family and supporters still believe he could be found alive because he had extensive survivor training and hiking experience, Sahota told CBC News in an interview earlier this week, before the reward had been doubled.

Srawn was a Canadian Forces reservist from 2005 to 2011, belonging to the 31 Service Battalion's Hamilton Company. Sahota told CBC Hamilton that Srawn had risen to the rank of master corporal and was responsible for his own unit.

That unit did forced marches and cold weather training in northern Ontario, Sahota said.

"They would do sustained cold weather training, with like two or three weeks of being in the middle of the forest with minimal equipment as part of their training. His report indicates that he did all of that with flying colours," he said.

The unit would often train in temperatures as low as –25 C, Sahota added.