Commercial vessel biofouling requirements

If you're bringing a commercial vessel into New Zealand, you need to meet the requirements of the Craft Risk Management Standard (CRMS) for Biofouling. Find out the requirements and how to meet them.


Ensure you have a clean hull before your vessel leaves for New Zealand

A clean hull may reduce any additional biosecurity-related costs and delays, should unforeseen itinerary disruptions occur.

  1. Get ahead of your biofouling: organise an underwater inspection and act on all biofouling found.
  2. Ensure that your most recent underwater inspection or underwater cleaning report is supplied to MPI.
  3. Ensure that all other relevant paperwork is supplied to MPI.
  4. Let MPI know as soon as a delay becomes likely.
  5. Reach out to MPI prior to departure for New Zealand if you are unsure of whether to carry out biofouling, or to seek further advice.

Following these 5 steps improves the likelihood of MPI granting a request to extend your itinerary. 

Port congestion: Vessel delays – suggested steps to take before coming to New Zealand [PDF, 360 KB]

If you have any questions, email:, or 

What are commercial vessels?

Commercial vessels generally move at medium to high speeds and aren't likely to be stationary for long periods of time.
They include:

  • commercial cargo vessels
  • trading ships
  • container ships
  • bulkers
  • cruise vessels.

What you must do

Most commercial vessels fall under MPI's short-stay category when arriving in New Zealand. Short-stay vessels are those planning to be in New Zealand for 20 days or less and only visiting designated ports.

Short-stay vessels should meet the CRMS requirements by providing evidence of continual hull maintenance following best practices.

Continual maintenance of commercial vessels

Continual maintenance involves ongoing management of biofouling, including:

  • developing and maintaining a Biofouling Management Plan specific to the vessel
  • keeping records of biofouling management in a biofouling record book
  • coating the hull and niche areas with antifouling paint appropriate to the operating profile of the vessel
  • regularly inspecting and cleaning the hull and niche areas
  • having contingency plans in place to minimise fouling if the vessel falls out of its operational  profile.

Providing evidence of continual maintenance

Before you arrive, MPI will ask to see evidence that you've used the above measures. Evidence must be verifiable and may include:

  • your Biofouling Management Plan and record book
  • dates and reports of dry docking
  • current antifouling system certificates
  • vessel operational history
  • evidence of independent inspections and ongoing maintenance (such as cleaning or treatment) by suitably qualified people.

Use suitable hull antifouling

The vessel hull should be painted with antifouling that can prevent biofouling between dry dockings.  When choosing an antifouling paint, you should take into account:

  • the planned time between dry dockings
  • the ship's speed and activity
  • any periods that the vessel will be stationary.

Where antifouling paint is damaged, consider in-water repair of the paint in the area, even if minor. 

Maintain, inspect and clean niche areas

Niche areas are protrusions, recesses, or unpainted areas of the hull, that are particularly susceptible to biofouling. It is important to show evidence that you've managed all niche areas for biofouling.

Vessel with close ups of niche areas: rudder hinge, propeller, sea chest, bilge keel and bow thruster

Sea chests

  • Paint internal surfaces with antifouling paints suitable for the flow of seawater.
  • Use marine growth prevention systems (MGPSs), such as chemical dosing systems, where possible.
  • Regularly use steam blow-out pipes if fitted in sea chests to reduce biofouling growth.

Sea inlet pipes and outlets

Apply antifouling paint inside pipe openings and pipework. Antifouling paint adheres and lasts longer if:

  • all sea inlet pipes and outlets have rounded surfaces – avoid corners where possible
  • grates on seawater intakes are made with round bars.

Hull appendages as niches

Any hull appendages can be niche areas, even when painted with effective antifouling. You should include them in your maintenance and cleaning programme.  Hull appendages include:

  • dry docking support strips
  • bow and stern thrusters
  • bilge keels, cooling scoops and propulsion scoops
  • rudder hinges and stabiliser fin apertures.

Hull appendages that can't be painted with antifouling paint – because it affects their operation – may need additional maintenance and cleaning. These include:

  • anodes
  • velocity probes
  • echo sounders.

Internal seawater systems

Effective marine growth protection systems (MGPSs), such as chemical dosing systems, can be fitted to internal seawater systems prone to biofouling. Use these systems regularly and monitor them to make sure they're working well. If MGPSs haven't been fitted or haven't prevented biofouling, treat internal systems before arriving in New Zealand.

Craft Risk Management Plans

Some commercial vessels, such as cruise vessels, may not be able to meet the requirements of the CRMS using one of the methods outlined in the standard. These vessels are encouraged to develop a Craft Risk Management Plan (CRMP) that outlines alternate but equivalent ways of managing biofouling.

Download the application form and guidance for developing a CRMP [PDF, 949 KB]

Find out more

Who to contact

If you have questions about biofouling requirements for commercial vessels, email 

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