A Chinese domestic airline's flights to and from Urumqi in Northwest China's Xinjiang Uyghur Autonomous Region were reported to provide only halal food on board, causing some passengers to worry that a uniformly Muslim menu threatens China's secularist principles.

On Wednesday, a passenger surnamed Zhang wrote on his Sina Weibo account "PETG (People for the Ethical Treatment of Green)" that he was only offered halal food on his China Southern Airlines (CSA)flight to Urumqi from Lanzhou in Northwest China's Gansu Province on May 10.

"I am not a Muslim, and forcing me to eat halal food is infringing on my freedom of religious belief," Zhang told the Global Times on Wednesday.

When he refused the meal, Zhang was told that there was no non-halal food on the flight. When he called to book a return ticket, he was told by a CSA support staff member that all flights departing from Urumqi only provide halal food on board.

However, the customer service branch of the airline denied Zhang's claim. "It's not true that all flights departing from Urumqi only provide halal meals. Passengers can book a meal in advance if they have any special needs, such as halal food," a customer service employee at the Urumqi office of CSA said when reached by the Global Times on Wednesday.

Neither a CSA spokesperson nor the airline's publicity department had replied to an interview request from the Global Times as of press time.

According to CSA's website, the airline is capable of providing many "special meals" - including those prepared for Hindu, Muslim and Jewish passengers - which can be booked 24 hours before the flight takes off.

Zhang's experience has been echoed by some other passengers who were exclusively offered halal food on domestic flights. Some Net users even wrote on CSA's Weibo account that they would boycott the company for ignoring the needs of atheists and followers  of other religions.

A woman surnamed Jiang told the Global Times that she was told by a Shenzhen Airlines attendant that only halal food was available during her March 2015 flight from Zhengzhou, Central China's Henan Province to Nanning, South China's Guangxi Zhuang Autonomous Region.

"Airlines in non-religious countries should not provide only halal meals on board," Xi Wuyi, an expert on Marxism at the Chinese Academy of Social Sciences who openly opposes national legislation on halal food, told the Global Times.

She added that airlines should prepare enough non-halal food for non-Muslim passengers.

Airline workers who spoke to the Global Times on condition of anonymity said Wednesday that they have never heard of a Chinese domestic flight only providing halal food, adding that only a few Chinese airlines adopt such a practice aboard flights to predominantly Muslim countries.

A recent proposition regarding national legislation on halal food sparked much controversy, as many scholars questioned whether the law would authorize the secular government to define Islam-related issues.