The large swamp fire burning in Waikato's Whangamarino wetlands is still not contained

The blaze, near Meremere, has burned through more than 520 hectares in the environmentally-significant area - since it broke out on Monday afternoon.

Crews will continue to monitor the fire overnight, with operations picking up again at first light.

Locals are advised to keep windows and doors closed - and those with water tanks should disconnect the pipe, if it has any ash and debris on the roof.