A post-mortem examination will be carried out today on the body of a German tramper found late yesterday in Mt Aspiring National Park near Queenstown.

Julian Stukenborg had been missing for 10 days after going tramping alone on the Cascade Saddle.

Senior Constable Mike Johnston says the 23-year-old's body was found during an aerial search.

"His body was found about 250 metres below the Cascade Saddle ridge line down into the Matukituki Valley which is a very steep, treacherous area," he told Newstalk ZB.

Mike Johnston says it appears Mr Stukenborg had slipped and hadn't been able to stop his fall.

- Newstalk ZB