A Wellington woman has been removed from a domestic Jetstar flight after violating the airline's pregnant passenger policy - but had been able to travel with the same airline just four days earlier.

Fairfax media reports 35-weeks-pregnant Sarah Clear had flown to Auckland to visit a sick friend. However, when she went to fly back to Wellington four days later, she was told it was Jetstar policy for pregnant passengers to have a clearance letter from a medical professional to fly.

After she had boarded the plane, a flight attendant asked Clear if she was pregnant. A manager then told Clear she would have to disembark.

Clear got off the plane and called her midwife, who told Jetstar she was okay to fly - but the airline said confirmation over the phone was not acceptable.

Clear eventually caught a flight back to Wellington with Air New Zealand.

She says she is upset Jetstar did not enforce their pregnant passenger policy on her first flight.

"I have argued black and blue with them that if they're going to stick to a policy, they must stick with it both ends. You can't strand me in Auckland," she told Fairfax.

She said if she had been aware of the policy, she would have arranged for the required letter.

Jetstar says it has apologised to Clear for the inconvenience and refunded her Wellington ticket.