Strike action for 200 workers at the Lyttelton Port has begun which could have significant effects on the whole of the South Island.
Two-hundred workers that belong to the Rail and Maritime Transport Union (RMTU) are now on strike after mediation talks to reach pay settlements failed.
Union members will picket outside the port on Tuesday and are expected to continue to strike for the next 13 days.
Canterbury Employers' Chamber of Commerce Chief Executive Leeann Watson says the strike will affect the whole South Island.
She says it's significant, given the port handles freight for Canterbury and the wider South Island and could have an impact on cashflow for exporters.
The sticking point is the port company's withholding of wages from those left without work when strike notices were withdrawn last week.
"We've tried everything including mediation to reach a settlement, but the company refused to amend their position and walked out before lunchtime," RMTU South Island Organiser John Kerr says.
"Port workers put two meaningful options on the table and asked if there was any ability to move on them. They were flatly rejected and LPC said they were not prepared to change their offer."
Lyttelton Port Company (LPC) says it is very disappointed that the strike will proceed.
The port had to divert ships over the weekend due to short notice of the withdrawl of strike action by union members.
"International shipping does not usually allow for vessel diversion at short notice," LPC Operations Manager Paul Monk says.
"Managing the return of vessels to our Port this weekend (10 -11 March) came at a significant cost and disruption to shipping lines, Canterbury shippers, importers and exporters who had already diverted cargo to other Ports."
The port remained committed to resolving the industrial situation but believed that RMTU's expectations were unreasonable which made it extremely difficult to reach a settlement, he says.