A ship course plotted by a cadet almost led to a repeat of the Rena disaster before a harbour pilot spotted the mistake and had the vessel steered away from rocks.
The near-miss that nearly led to a grounding at the Wellington Harbour entrance is among 13 serious incidents involving ships reported to authorities since the MV Rena slammed into Astrolabe Reef and caused our worst environmental maritime disaster.
Disclosed to the Herald by Maritime New Zealand, the incidents have revived calls for New Zealand to introduce tougher navigation laws for ships - something the Bay of Plenty region is now considering. But the Government reaffirms it has no plans to adopt compulsory shipping lanes.
In the most serious case among documents obtained under the Official Information Act, in August last year, the 193m cargo ship AAL Brisbane was headed for Pencarrow Rocks in the Wellington Harbour when the harbour pilot came aboard.
The ship was found to be 600m off course, with the GPS feed to the ship's ECDIS (electronic chart display and information system) described as "grossly in error".
An internal memo stated the ship's course was being plotted by a cadet. "Fortunately the harbour pilot came onboard, noticed the error, and adjusted the course of the ship - avoiding a grounding."
The incident prompted Maritime New Zealand to hold an emergency meeting and the ship to be temporarily detained in port.
In the same month, the Interislander ferry Kaitaki had to alter course when a gas tanker failed to give way in the Cook Strait.
The incident was one of four reported incidents involving the same ferry being forced to take action when encountering other vessels.
In another case, at Marsden Point near Whangarei, a small power boat was motoring toward an oil tanker at full speed in early morning darkness when it turned away, narrowly avoiding impact.
The AAL Brisbane's near-miss has been highlighted as an example why the country needs better shipping routing systems.
Marico Marine senior partner John Riding has tracked ships cutting too close to land as often as every two days, including a 280m cruise liner monitored while sailing through the Mercury Islands.
Ships in New Zealand open waters must comply with a list of rules that require competency, compliance with collision regulations, an electronic system that identifies them and for crews to develop passage plans for their navigation around coasts.
But Mr Riding said if a Government did not introduce a new system where authorities would plot GPS-guided routes for ships, it was a matter of time before another ship grounded. "What we've got now is a free-for-all - and you don't have to look very hard to know the free-for-all isn't actually working," he said.
"If we made it so ships have a passage plan and they've got to pass through a, b and c, you can seriously influence where the ships go."
Mr Riding believed what he saw as "prevention" would prove far less expensive than dealing with ships after they grounded.
Opposition MPs are also calling for a crackdown. "I think the Government should be directing Maritime New Zealand to take a closer look at this - and it's a good example of where the Government taking a hands-on approach and re-establishing some light-handed regulation that helps to improve safety could be very sensible," Labour transport spokesman Iain Lees-Galloway said.
Green MP Gareth Hughes, who backs compulsory shipping lanes, accused the Government of downplaying the risk of further accidents since the Rena disaster.
"The Rena captain himself recommended the use of compulsory shipping lanes but the Government rejected the idea."
Mr Hughes said the near-misses were also an urgent reminder that the country needed a better oil spill response capability.
New Zealand Shippers' Council chairman Greg Steed said any new system put in place would have to be "safe and pragmatic" for a country the size of New Zealand.
Shipping New Zealand president Captain John Robinson said shipping lanes could slightly extend travelling distances, but "if it improves the safety, then it's got to be accepted really by most lines".
A Ministry of Transport spokesperson said the country had low levels of shipping traffic by international standards and compulsory lanes were generally used in areas with narrow waterways or large concentrations of vessels; to keep ships with hazardous cargo clear of coasts; and where navigation was hazardous.
The ministry would go over issues and any evidence with Maritime New Zealand before deciding whether it would review regulations.
The spokesperson said the Transport Accident Investigation Commission's report on the Rena disaster - due some time after July - was "likely to be of particular relevance".