Terrified passengers who were thrown around and injured or shocked when QF72 suddenly plunged have been offered compensation by Qantas, depending on whether they were travelling business or economy class.

The airline has pledged to give each passenger on the turbulent flight from Singapore to Perth a voucher - ranging in value from $2000 for economy travellers to about $6000 for those in business class.

It will also refund all tickets and pay medical expenses resulting from the incident on Tuesday.