Chinese airlines had a slight scramble on Monday after they were ordered to ground their Boeing 737 Max 8 aircraft as China became the first country to take the precautionary move following a second crash of the model in five months.

In a circular on Monday morning, the Civil Aviation Administration of China said it made the decision to halt all B-737 Max 8 flights by 6pm that evening as there was "a degree of similarity" between Sunday's Ethiopian Airlines crash and the Lion Air crash last October.

The move is significant because China operates the largest B-737 Max 8 fleet, with 97 planes, or over a quarter of global deployment.

The aviation authorities in at least six other countries, including Singapore and Australia, have done the same, as have about 25 airlines.

Chinese data provider VariFlight said that of the 355 flights planned for B-737 Max 8 jets on Monday, at least 29 were cancelled, though the majority were switched to other planes.

However, the inconvenience was temporary. When The Straits Times visited Beijing Capital International Airport yesterday afternoon, the terminals had their usual mid-week crowds.

China's three largest airlines - Air China, China Southern and China Eastern - which together operate just over half of the country's B-737 Max 8 jets, said they had fully switched to other models.

Passengers booked on flights previously planned for the B-737 Max 8 had been notified by SMS about the change in planes, they added.

"There might have been a bit of commotion on Monday, but it was mainly because some of the replacement planes may have different configurations so there might not have been enough premium economy seats," said Air China customer service officer Dong Zhimo.

"But Chinese airlines generally have enough planes in reserve ."