An employment dispute with airport staff is taking off this morning.

Lockout notices are now being issued against security workers who were planning on striking for three hours later this month in Auckland Wellington and Christchurch, beginning on the 20th.

E Tu Union said it was because of stalled pay talks that had lasted more than a year.

The strike would be the first in 30 years from airport security staff.

The union now says it has received lockout notices, and its legal team is looking this morning into exactly what they mean.

It's hoped a mediation meeting next Friday might prevent chaos for travellers hoping to fly during the school holidays.

Aviation Security Service Group Manager Karen Urwin said they think their pay offer is fair, but if a mediation meeting on the 15th doesn't go well, they have contingency plans in place for airports.

"We have staff who are on individual employment agreements. We have staff in management positions and we have staff who are doing other roles across the sector who are all qualified to screen."

Ms Urwin said they're aware it will be the school holidays and families will be looking to get away, so they'll do everything they can to minimise disruption.

Prime Minister John Key has said an option is to bring in other agencies like Police or Customs to do the job.