TAIPEI — A strike by staff from Taiwan’s largest carrier China Airlines left 20,000 passengers without flights today in the first industrial action by cabin crew in the island’s aviation history.

The airline was forced to cancel all flights out of the two main airports in the capital Taipei, with the only exception a chartered service for President Tsai Ing-wen who left for a state visit to Panama and Paraguay today morning.

Crowds of passengers queued up at CAL counters in Taipei’s Songshan and Taoyuan airports today morning as the airline tried to get them onto different flights.

Hundreds of flight attendants staged a sit-in outside the firm’s headquarters in Taipei overnight, protesting a new requirement that they report for work in Taoyuan -- on the outskirts of Taipei -- rather than downtown Songshan.

They say the measure was brought in "unilaterally".

"(It) pressures us to work even more overtime and will seriously affect flight safety," the Taoyuan Flight Attendants Union said in a statement on its Facebook page.

The union is also calling for other improvements to conditions, including double pay for working on national holidays.

The official strike started at midnight. Protesters continued to sit-in outside the CAL office today.

Both the president and the chairman of CAL were replaced yesterday after tendering their resignations before the strike.

Incoming chairman Ho Nuan-hsuan is due to take office today when his appointment is officially approved by the board of directors.

Ho, appointed by the transport ministry, which is CAL’s largest shareholder, is reportedly in favour of granting the union’s request to drop the new requirement for crew to report in to Taoyuan.

In a statement today, CAL urged the government to intervene to bring the strike to a "smooth end", saying the union was unwilling to negotiate.

It described the strike as an "unauthorised surprise attack" on the airline.

Tsai gave her thanks to the flight attendants during a short speech before her departure and vowed the government would defend their labour rights.

CAL’s vice president said today it was trying to get passengers onto other flights but that it was difficult in peak summer season.

Flights from the southern cities of Kaohsiung and Tainan were unaffected today. — AFP