Waikato District Health Board says hundreds of people who applied for jobs with the board in the past week may need to reapply.
The DHB says it is investigating a problem with the server it uses for online job applications and it is not yet clear what happened.
The closing date for 17 jobs passed this week and the board estimates up to 250 applications may need to be made again.
Human resources general manager Fiona McCarthy says the DHB usually gets about 50 job applications a day and that can rise to about 100 near the closing date for advertised positions.
She says the server is working again and people should resubmit any applications they made in the past week.
Ms McCarthy says the health board gets applications from all over the world including Australia, the United Kingdom and India.