SYDNEY, March 6 (Reuters) - Australia's Qantas Airways has been fined A$250,000 ($162,375) for illegally sacking an employee who told staff not to clean aircraft arriving from China early in the COVID-19 pandemic, adding to the airline's reputational challenges.

The New South Wales state district court issued the fine on Wednesday after finding the carrier guilty last year of "discriminatory conduct for a prohibited reason" over the firing. The charges were brought by the state's workplace safety office, SafeWork NSW.

The employee, Theo Seremetidis, a lift truck driver at Sydney airport, raised concerns in February 2020 about the safety of workers assigned to clean aircraft arriving from China, SafeWork said.

He used his position as a union health and safety representative to order workers not to clean the planes, and Qantas fired him, according to SafeWork. The airline was fined in addition to being ordered to pay Seremetidis A$21,000.

"No work health and safety rep should be stood down for doing their job," New South Wales Work Health and Safety Minister Sophie Cotsis said in a statement.

"Let this case stand as a warning, not just to Qantas but to all employers, not to discriminate against their health and safety reps."

Qantas said it accepted the penalty and noted that it had "acknowledged in court the impact that this incident had on Mr Seremetidis and apologised to him".

"Safety has always been our number one priority and we continue to encourage our employees to report all safety related matters," the airline added.

The penalty comes as Qantas seeks to win back investor and public support after a string of lawsuits and controversies resulted in the early retirement of its long-standing CEO Alan Joyce last year.

The airline is still waiting to learn how much it must pay after losing a separate lawsuit accusing it of illegally firing 1700 ground staff in 2020 to stop them from taking industrial action such as strikes.

It is meanwhile defending a lawsuit from the Australian Competition and Consumer Commission accusing it of selling tickets to thousands of flights after they were cancelled amid staff shortages and high demand after the country's border reopened in 2022. ($1 = 1.5396 Australian dollars) (Reporting by Byron Kaye; Editing by Jamie Freed)