Cathay Pacific staff who join a planned Hong Kong strike will be fired.

The airline has warned staff about the risks involved as a crackdown on employee support for the widespread protests has intensified.

Hong Kong's flagship carrier employs 27,000 staff in the city.

Cathay has been accused of bending over to accommodate China as political pressure is increasingly exerted on the airline.

The China aviation regulator has banned airline staff who have supported the demonstrations from working on flights through its airspace.

Internal memo

A Cathay director, Tom Owen, said in an internal memo to staff that participating in a strike planned for Monday and Tuesday, Sept. 2 and 3, could constitute a breach of contract.

Cathay sent a copy of the memo to AFP.

Between Sept. 2 and 3, many people from different walks of life would stop working if the Hong Kong government continued to turn a deaf ear to the people, the city’s public broadcaster RTHK reported.

The memo said: "We expect all of our employees to report for work as normal and over this period and will be monitoring attendance levels closely."

"Any breach of policy or regulatory requirements will be investigated and may lead to termination of contract."

Cathay's latest warning is a u-turn from its previous position earlier in August of being publicly supportive of the right to free expression of its workforce.

Cathay has since sacked at least four staff, including two pilots, for supporting the protests.

A fifth, Rebecca Sy, a union organiser and cabin crew for its regional airline Cathay Dragon, has been dismissed without explanation.

Witch-hunt

Cathay staff believe there is a witch-hunt in the airline, a phenomenon referred to as "white terror" following the departure of its well-loved CEO Rupert Hogg on Aug. 16.

Employees have deleted social media posts and purged friends from friends lists as any association with protests elements can result in disciplinary action.

Cathay has revised its code of conduct to employees, reiterating its "zero tolerance" approach to "illegal protests" participation by staff.

Cathay reputation tarnished

Protest groups are calling for a general strike on Monday and Tuesday.

A city-wide strike early August brought transport chaos to the city and that movement was supported by Cathay's flight attendants union whose members joined the walk out.

More than 160 flights were cancelled as a result.

Cathay's 72-year reputation as a totemic Hong Kong company is now tarred, critics have said.