An Australian couple have criticised Qatar Airways after a blanket-covered dead body was seated next to them during a long-haul flight.

Mitchell Ring said a passenger died part-way through the 14-hour flight from Melbourne to Doha last week.

"They tried to wheel her up towards business class, but she was quite a large lady and they couldn't get her through the aisle," he told Australian network Nine News this week.

"They looked a bit frustrated, then they just looked at me and saw seats were available beside me."

Ring said he was made to wait next to the corpse even after the plane landed.

"The ambulance officers and the police came in, and the ambulance officers started pulling the blankets off the lady," he said.

"It wasn't nice."

Ring and wife Jennifer Colin were seated next to the corpse while travelling to Venice.

Ring said he was seated with the body for around four hours despite other empty seats.

In a statement to Australian media, Qatar Airways apologised "for any inconvenience or distress this incident may have caused".

"First and foremost our thoughts are with the family of the passenger who sadly passed away on board our flight."