Union members involved in partial industrial action at hospital laboratories have issued notice that they will extend it until September.
About 1000 union members at labs in public hospitals are in a pay dispute with district health boards over a new collective employment contract.
It has led to the suspension by the three DHBs in Auckland of about 30 lab workers per day for the past week.
The Medical Laboratory Workers Union confirmed on Friday it has given notice of an extension.
DHBs in Auckland, Northland, Wellington, Hutt Valley and Canterbury and the New Zealand Blood Service have been told to expect it to continue until September.
A postal ballot of union members on a revised pay offer is to close on Monday.