Two people are not expected to have survived a plane crash in North Queensland.

A 73-year-old man and a 75-year-old woman are believed to have been on board the light aircraft when it went down in the Pioneer Valley west of Mackay on Saturday.

A police spokesperson said emergency services were alerted to the crash about 9am.

A rescue helicopter crew located the crash site in the Pioneer Valley about 11.30am. 

The spokesperson said the crash was unsurvivable and the pair are presumed dead.

The plane crashed in mountainous terrain.

The Australian Transport and Safety Bureau has been notified of the crash and will conduct an investigation.

The Forensic Crash Unit will also investigate on behalf of the state coroner.