Passengers affected by Air New Zealand Christmas cancellations may not be covered by insurance

The disruption caused by Air New Zealand's cancelling flights over the holiday season could get a lot worse for those travellers who haven't booked travel insurance.

On November 18, Air NZ revealed a list of 80 flights that would be impacted by urgent maintenance work required on engines used by the airline's Dreamliner fleet.

According to financial service provider Allianz Partners, if passengers signed on for travel cover after 12pm on Wednesday November 20, then they may not be covered.

"We will not pay any claim caused by or in any way connected with this event," the company said in a statement.

The company says it's assumed and expected that the person travelling who purchased the travel insurance after that time did so "with an awareness of the flight cancellations."

Travellers who booked insurance before November 20 will likely you will be covered for any costs incurred due to Air NZ's engine issues and flight cancellations.

Allianz Partners says it's important to check the fine print on travel insurance policies, as some passengers may not be covered at all.