Strikes today and Friday by medical lab workers - could lead to five straight days of testing site shortages countrywide

APEX union says workers at private providers Awanui Labs, Pathlab Limited and Medlab are paid up to 32-percent less than those doing the same work for Health New Zealand.

Many locations are also closed on Waitangi Day and over the weekend.

New Zealand Pathology Chair Peter Gootjes says the impact will differ by region.

He says community samples won't be available across the whole South Island, Gisborne and Whanganui - but other locations are slightly less affected.