Mr Nazari, an experienced bushwalker, was last seen by friends about 2.30pm on Boxing Day, making a difficult descent down what is known as the Hannels Spur trail in Kosciuszko National Park.
He then failed to meet two friends at the Geehi campground and they began the search that escalated with teams joining from NSW Police, the State Emergency Service, the National Parks and Wildlife Service, NSW Ambulance and volunteer rescuers.
Hadi Nazari was last seen on the Hannels Spur trail in Kosciuszko National Park. (HANDOUT/NSW POLICE)
Rubbish and hiking poles believed to belong to Mr Nazari were found late on Tuesday near the Kosciuszko River, narrowing the search to focus on this area.
"We are continuing to search for Hadi," Acting Superintendent Jill Gibson said on Friday.
"We are not giving up hope of finding him alive.
"Our search crews are focusing on creek lines and water sources, where we believe Hadi may be."
Additional specialist teams have been deployed with winching capabilities, enabling officers to access denser bushland and extend their search into remote locations.
Specialist bushwalkers have joined the search effort as it approaches its 10th day. (Supplied by Nsw Police/AAP PHOTOS)
Aircraft from multiple emergency crews are also assisting, but the rugged terrain and dense vegetation is providing significant challenges.
"The bushland (is) so dense that searchers – in some parts – can't see their feet," A/Supt Gibson said.
"We know Hadi is an experienced bushwalker, so we will continue through the weekend searching to try to locate him."
Search and rescue specialist Paul Luckin, who has assisted police with the search, said that of the 105 searches he had joined in the past year, just three people had been found alive after long periods alone in the wilderness.
"We don't have many who are missing for an extended period and come out alive," he told AAP.
"Ultimately, his survival is going to depend on finding drinkable water and probably staying at that water."
Police remain hopeful of finding missing bushwalker Hadi Nazari against the odds. (Supplied by Nsw Police/AAP PHOTOS)
Dr Luckin said the availability of water in the area where Mr Nazari went missing was scarce.
"Whether you can find water or not depends on the terrain and how thick the vegetation is, it is well known that the vegetation in that particular area is very dense, very thick vegetation," he said.
"There is some water (there), but accessing it is difficult."
The Hannels Spur trail is regarded as one of Australia's most challenging bushwalking trails, with an 1800m change in elevation.
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