Cabin crew at South African Airways (SAA) went on strike on Wednesday over pay benefits, a top workers’ union at the state-owned carrier said.

The strike disrupted domestic flights and threatened to extend the walkout to international routes.

The South African Cabin Crew Association (SACCA) said that its nearly 1,400 in-flight workers would down tools indefinitely.

Zazi Nsibanyoni-Anyiam, President of SACCA, told Reuters that the workers, who represent around 80 per cent of SAA’s cabin crew, had not received pay increases for six years.

“We will be here until the company puts an offer on the table. We think what we are asking for is reasonable,” Nsibanyoni-Anyiam said from a picket outside O.R. Tambo Airport in Johannesburg.

SAA said that the strike had already delayed flights out of the airport, which handles around 19 million passengers a year.

It added that the strike would affect flights from its coastal airports.

SAA is reliant on government debt guarantees of almost 20 billion rand ($1.52 billion).