By Jack Gramenz

A search is resuming for a missing hiker a week after he was last seen, with hiking poles and rubbish located as agencies scour the rugged terrain.

The 23-year-old hiker, Hadi Nazari, was descending a challenging trail in the Kosciuszko National Park about 2.30pm on December 26 when he was last seen by friends, who raised the alarm when he did not arrive at the campground where they arranged to meet.

NSW Police, the National Parks and Wildlife Service, State Emergency Service, NSW Ambulance and volunteer rescuers have been searching for Mr Nazari ever since.

Rubbish and hiking poles believed to belong to Mr Nazari were located late on Tuesday evening but he is still yet to be found.

He was not carrying a personal locator beacon but was thought to have a reasonable amount of water as well as camping gear, police have told reporters.

A helicopter with infrared imaging technology has also been used in the search and specialist crews have been flown into the rugged terrain.

Mr Nazari was last seen on the Hannels Spur Track between Khancoban and Thredbo in the national park.

It is regarded as one of Australia’s most challenging bushwalking trails, with an 1800m change in elevation.

“It’s part of the most rugged terrain in NSW, it’s very steep, it’s very vegetated, and it’s quite remote,” NSW Police acting Superintendent Jillian Gibson told reporters earlier in the search.