APEX has called off nationwide strike action involving sonographers.

The workers, who carry out ultrasound scans, issued strike notices for staff at Palmerston North, Wellington, Dunedin, Invercargill and Gisborne DHBs.

Further strike notices were also coming for Hawke's Bay, Hutt, Wairarapa and Bay of Plenty DHBs.

The action comes after a break down in pay negotiations, which have been going on for 15 months.

APEX spokeswoman Mary Bull says following further communication with DHBs at the end of last week, all strike notices have now been lifted.