Fire and Emergency New Zealand crews have been working to battle a large vegetation fire in the Whangamarino wetlands since 7am this morning, as well as on Monday afternoon.

Incident Commander Mark Tinworth says the fire is not yet contained, and crews will continue to monitor the fire overnight, with firefighting operations continuing at first light.

"Aircraft supported by ground crews have worked really hard today," he said.

The fire now has a perimeter of 11 kilometres and has burned through more than 520 hectares in the Island Block area.

If there you see or smell smoke outside, stay inside and keep windows and doors shut.

If you have roof water supply, disconnect the pipe to your tank if there is a lot of ash and debris on your roof.

The next update will be around 9am, Tuesday 23 October.

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