Hundreds of medical lab workers are beginning a week-long rolling strike from today

The union, Apex, says 850 workers from Awanui, Pathlab, and Medlab will join the strike - impacting over 70-percent of New Zealand towns and cities.

It estimates more than 120-thousand patient tests will be impacted.

National Secretary Deborah Powell says workers are fighting to close a 30-percent pay gap with Health New Zealand.