Further strike action is on the cards at the Lyttelton Port after negotiations between the managing company and a union failed again.
The Rail and Maritime Union's 200 members at the port - about half its staff - have been embroiled in a dispute with the Lyttelton Port Company over pay and safety.
They want to be paid the same as the members of a rival union working at the port.
Port management said it would only accept this if workers agreed to work the same flexible hours as the rival union.
This led to the first strike action in March, effectively closing the port.
RMTU organiser John Kerr said more strike notices had been issued for five days from 20 April because the company had rejected union compromises.
However, port chief executive Peter Davie said the company put three offers to the union today, but they were rejected.