A 43-year-old man was still missing in Kosciuszko National Park on Monday evening, after rescuers searched for him for hours from the air and on foot.

Emergency services say the man from Kalkite, near Jindabyne, went to Dead Horse Gap near Thredbo about 1am on Monday morning.

It is understood he was hoping to walk to Ramshead Range to photograph the sunset but called a friend around dawn to tell him he was lost.

Police from Monaro Local Area Command responded to a call about the lost man about 11am.

The Wespac Lifesaver Helicopter joined in the search soon after.

About 2.30pm, Westpac Lifesaver CEO Stephen Leahy said he was concerned for the bushwalker as he was stuck in hedge-high grass.

"He managed to call police, but searchers on the ground can't locate him, so we're flying up now to commence that search," he said.

"With only 2.5 hours of light left, every effort is being made to try and find him before night falls."

Night fell and the search continued.

At about 4.30pm, Mr Leahy said a police officer from Thredbo Village to was helping search a small area west of the village.

Three hours later, he said the helicopter search would commence in the morning.

"Severe turbulence really played havoc with us this afternoon," he said.

Around the same time, a NSW Police spokeswoman said the search had still been continuing on the ground at 6pm but was expected to stop throughout the night and resume in the morning.