Australian actress Nicole Kidman has found herself under fire from the Association of Professional Flight Attendants over her new ad campaign for Abu Dhabi-based Etihad Airways, with the union calling into question her credentials as a feminist.

“Last month, on March 8, International Women’s Day, you said, ‘I envisage a world where all women and girls have equal opportunities and rights ... Now is the time to step it up',” the president of the association, Laura Glading, wrote to Kidman in an open letter. “Later that very same week, we saw that you had begun appearing in a new campaign for Etihad, a company that the Wall Street Journal has publicly reported ‘may fire women if they become pregnant’ and forces flight attendants to live in ‘confinement’ in secure compounds’."

Kidman appears in a new commercial for Etihad that is being shown inflight to promote the new A380.

Etihad has spoken out against the union’s accusations, rejecting any criticism of its maternity policy for flight attendants.

"When a cabin crew member informs Etihad of a pregnancy, she is provided with appropriate ground duties for the duration of their pregnancy. During this time, she remains fully compensated and fully engaged on the ground,” the airline said in a statement. "Cabin crew are also entitled to paid maternity leave if they have completed more than one year’s service. Our cabin crew are then able to return to their flying role at the end of their maternity leave period. The health and safety of our cabin crew remains paramount. Therefore, we follow the GCAA requirement that crew do not continue to fly while pregnant."

In the letter to Kidman, Glading had chided the actress over Etihad having “conditions that Apfa fought to eradicate decades ago in the United States;” however, the United States is the only developed country in the world that does not require paid maternity leave.

The attack on Etihad comes weeks after similar criticism of Qatar Airways, which the airline also denied – though its chief Akbar Baker did admit that flight attendants with less than three years on the job were not guaranteed a ground position if they became pregnant.

The rise of the major Gulf carriers has seen a flurry of criticism and attacks from Western competitors - from the accusations of poor treatment of workers to allegations of illegal subsidies .

As some of the fatest growing international carriers, Etihad, Emirates and Qatar Aiways are likely to remain under the microscope for quite a while.