Lyttelton Port of Christchurch is expecting to be operating by tomorrow, when a fuel ship is due to arrive for unloading.
The port, which sustained tens of millions of dollars' worth of damage in September's earthquake, was further damaged in the earthquake on Tuesday.
Infrastructure and facilities where closed, but no staff were injured.
While Port Otago has said it has extra capacity to host temporarily any vessels not able to call at Lyttelton, PrimePort Timaru has handled a container and fuel vessel, and assisted the latter to get fuel to Christchurch.
Timaru will take a fertiliser and container ship during the next three days, and possibly other vessels next week, NZPA reported.
Chief executive Peter Davie yesterday said engineers and civil maintenance staff had since carried out extensive structural checks and found the oil berth and container wharves "had held up well", although the latter required some urgent minor repair work.
Mr Davie praised the Royal New Zealand Navy, which had vessels in port at the time of the earthquake, for having divers assist engineers in assessing structures and carrying out soundings to review thechannel depth.
LPC aimed to have limited operations available within three to four days and estimated it could be fully operational within about 10 days.
However, the loading and unloading of cargo may not be available until some time today.
"Our clear focus is on ensuring that fuel and essential services will get through to Christchurch," Mr Davie said.
Solid Energy, which mines about 2 million tonnes of West Coast coal each year, is one of LPC's major customers and last financial year railed 1.7 million tonnes across the Southern Alps to Lyttelton for export.
Solid Energy chief operating officer Barry Bragg said the mine was still operating as usual but had started stockpiling coal on the West Coast until exports were under way again.
"We expect to issue force majeure notices for the interruptions to shipments that we suffer as a result of the Christchurch earthquake event," Mr Bragg said.
