Ballast water

New Zealand has some of the most pristine seas in the world. We need to protect our seas from unwanted foreign organisms. Find out about MPI's requirements to prevent organisms entering New Zealand in ballast water.

Rules to manage ballast water discharge

Marine pests and diseases carried in ballast water tanks can threaten our marine environments and seafood industries. To manage this risk, MPI has rules to control discharge of ballast water in New Zealand waters.

These rules are set out in the Import health standard – Ballast water from all countries. You must follow the rules in the import health standard to avoid unnecessary delays, costs, or possible legal action.

Download the import health standard for ballast water [PDF, 161 KB]

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Before arrival
Managing your ballast water, keeping records, and declarations.

Keep records of ballast water management

Keep records of the volumes, locations and dates of ballast water loading or discharge. Preferred record keeping templates are in the International Maritime Organisation (IMO) Convention for the control and management of ships' ballast water and sediments.

Treat or exchange ballast water

If you have ballast water from another country, you must not release it in New Zealand territorial waters without the permission of an MPI inspector.

To get permission to discharge ballast water in New Zealand, you need to ensure your ballast water is one of the following:

  • adequately exchanged with mid-ocean water
  • fresh water - not more than 2.5 parts per thousand sodium chloride, or
  • treated using an approved shipboard system (from the list of MPI-approved ballast treatment systems).

Mid-ocean exchanges

You can reduce the risk of introducing unwanted marine organisms to New Zealand waters by exchanging ballast water mid-ocean. Carry out mid-ocean ballast water exchange in waters at least 200m deep and as far as possible (preferably 200 nautical miles or more) from land.

You can use either the empty-refill or the flow-through method to exchange ballast water.

  • Flow-through method – pump 3 times the tank volume through the tanks to dilute existing ballast water.
  • Empty-refill method – replace at least 95% of the water in the tanks.

Avoid loading ballast water from risk locations

If you are loading ballast on your vessel before coming to New Zealand, avoid taking water from places:

  • where harmful organisms or diseases, such as cholera, occur
  • near a raw sewage outlet
  • where tidal flushing is poor
  • where water is turbid.

Send ballast water declaration before arrival

Before your vessel arrives in New Zealand, you must send a ballast water declaration. This can be sent with your Advance notice of arrival form.

You must complete parts 1 and 2 of the Biofouling and ballast declaration if your vessel has ballast water. If you need to discharge ballast water in New Zealand, you must request permission by completing part 3. You can customize the forms to your vessel for future visits.

Completed forms are emailed (usually by your ship's agent) to

On arrival
Inspection and permission to discharge.

Prepare for arrival inspection

When you arrive, an MPI inspector may ask to see your original ballast declaration and ballast management records. The inspector may also talk with crew members about loading and exchange of ballast water, and may take ballast water samples for testing.

Get permission confirmed before you discharge ballast

Confirm that you have permission from MPI before you discharge ballast water in New Zealand. You can discharge ballast water in New Zealand waters when an MPI officer returns your ballast declaration form with approval to discharge ballast water.

Emergency discharges also require approval

You may be allowed to discharge untreated ballast in New Zealand if it was unsafe to discharge mid-ocean. Emergency discharge to protect the safety of your ship, crew and passengers is the only acceptable reason to release untreated or unexchanged ballast water in New Zealand waters.

You must seek approval from MPI for any emergency discharges. You must also notify an MPI inspector if you can't fully exchange ballast water that you planned to discharge in New Zealand.

Don't discharge sediment

Never discharge sediment from cleaning of ballast tanks, holds or anchor chain lockers in New Zealand territorial waters. You can only dispose of sediment at a landfill approved by a quarantine inspector.

Find out more

Who to contact

If you have any questions about ballast water requirements:

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