A search is continuing for two men who went missing while bushwalking in the NSW Blue Mountains.

The 69 and 81-year-old bushwalkers left from Dunphy’s campground in the Megalong Valley on Wednesday, telling a friend they would be back on Friday.

Police say the alarm was raised on Sunday when the 69-year-old failed to keep an appointment on Sunday and a search began.

The 81-year-old man’s car was found in the car park of Dunphy’s campground.

Searches are continuing on Monday afternoon, as temperatures in the area soared above 30C.

Officers looking for the pair are believed to have promising leads on where the bushwalkers may have hiked.

Both men are described as experienced bushwalkers and police believe the trail they intended to take was within their capabilities.

A command post has been established at Dunphy’s campground with local police, the rescue squad and SES involved in the search.