A fortnight-long strike at Lyttelton Port has not yet prompted any increase in export or import volumes at Port Otago, but that may change in the weeks ahead.
Despite a deal between the Lyttelton Port company and Rail and Maritime Transport Union having been close, 200 workers went on strike at midnight on Monday for a fortnight.
Maritime Union of New Zealand members at Lyttelton are under a separate agreement and are not striking.
Port Otago chief executive Kevin Winders when contacted said he was not aware of any changes having been made to shipping schedules, but did not rule out the fact importers might consider using Port Chalmers.
''Some shipping lines might omit a call to Lyttelton Port, and we might get some demand here.
''But then it comes down to the supply chain to get to destinations inland,'' Mr Winders said.
Using road transport to get goods from Port Chalmers back to Christchurch could be a ''very expensive'' option, he said.
''We're unaware of any shipping lines diverting at this stage.''
Lyttelton Port said the union had given notice of a two day strike, then withdrawn it, and ships were diverted to Timaru, which meant there was no work for staff on those days, and Lyttelton Port subsequently refused to pay any wages.
RMTU South Island organiser John Kerr was contacted yesterday and said the striking staff might not return to work until March 25.
He believed the situation amounted to an illegal lockout, and yesterday confirmed the union would file a claim in the Employment Relations Court today.
Mr Kerr said the strike was going ahead, albeit the union had two consecutive 24-hour strike notices in place, meaning the strikes could be called off at short notice if a meeting was agreed.
He said yesterday a meeting ''was not looking promising at this stage'' and the situation was ''not ideal'', given the pending financial loss to workers and hundreds of thousands of dollars' lost revenue for the port company.
Mr Kerr was asked if the strike could spread to other ports.
He said RMTU members at both Timaru and Port Chalmers were keeping ''a close watch'' on proceedings, especially if shipping was diverted to those ports.
''Sticking points now include LPC's insistence on docking the pay of workers who didn't take part in strike action last week, because they withdrew the strike notice,'' Mr Kerr said.
