More ships are expected to avoid Auckland by the end of the week due to industrial action, but Port of Tauranga's boss says there is no guarantee there will be room for them here.
Three weeks of strike action began on Monday at the Ports of Auckland, and, as a result, at least six more ships are expected to divert elsewhere by Sunday.
Port of Tauranga chief executive Mark Cairns said the port was already dealing with projects that had it brimming with business over the next few months, so it was unlikely the ships would berth here.
"There is no guarantee [of room for more ships].
"We are expecting a very busy period over the next few weeks and basically we are at capacity in the short term, until projects within our $150 million investment programme deliver increased capacity ... over the next 12 months."
On Sunday night, the Kota Permasan docked at Tauranga after a last-minute turnaround believed to have come from union pressure.
It was reported the ship's company, Pacific International Lines, was warned that its ships would be blacklisted around New Zealand and Australia - meaning union workers would refuse to unload them - if the Kota Permasan docked in Auckland and was serviced by non-unionised stevedores.
The company's New Zealand manager Arun Joshi told Radio New Zealand: "They were quite threatening in that respect. For us, it's commercially too much of a risk to take, to get a blacklisted ship."
Maritime Union New Zealand president Garry Parsloe denies any involvement.
The Kota Permasan left Tauranga at 1.30am yesterday.
Already 12 ships have diverted to other ports during seven strikes against Auckland's council-owned port company since early December, when about 300 workers were also locked out for 48 hours.
The company estimates its revenue loss so far from the diversions is up to $3.5 million, not counting hefty costs to importers and exporters unable to get goods to market in time.
Ports of Auckland general manager sales and marketing Craig Sain said the company would continue to rely on its non-union workforce.
"Our permanent stevedoring staff who are not members of MUNZ will handle a number of vessels over the next three weeks and are doing all they can to minimise the impacts on consumers and the supply chain. Six ships are diverting to other ports as part of arrangements we helped to put in place to manage the impacts of the strike action."