Etihad Airways on Friday vowed to keep fighting a lawsuit brought in Australia by a man who claims he hurt his back after being seated next to a sick, obese passenger.

Brisbane man James Bassos, 38, is seeking damages, reportedly Aus$227,000 (US$165,000), after claiming he suffered permanent health problems from being forced to twist and contort his body to avoid contact with the other passenger "whose body encroached into his seat".

The District Court in Brisbane on Thursday heard that the obese passenger also frequently coughed and "expelled fluid from his mouth" during the flight in economy class from Abu Dhabi to Sydney in 2010.

Bassos claimed that after five hours of discomfort he complained, but his request to be given another seat was refused. He was eventually allowed to use a crew seat, the Brisbane Courier Mail reported.

Etihad's lawyers last week attempted to have the case thrown out but District Court Judge Fleur Kingham refused their request and ordered Bassos to undergo a medical assessment.

The Abu Dhabi-based airline said it would continue to fight the lawsuit.

"Etihad Airways will continue to oppose the action and now that Mr Bassos will finally face a medical assessment in December 2015, as directed by court, we believe that the matter will proceed to an early conclusion," the carrier said in a statement Friday.

"The safety and comfort of Etihad Airways passengers and crew is of paramount importance and the airline has a zero tolerance policy towards unruly behaviour."