Police are seeking information from the public as they continue to investigate two fires believed to be intentionally lit in Nelson.

One was on Rabbit Island, on Wednesday February 6, and another on Iwa Rd around 2.30pm on Friday February 8.

Both fires were brought under control quickly utilising resources deployed away from fighting the Pigeon Valley fire.

The fire on Iwa Rd started near the lower end of the street and spread quickly up the hillside.

It had the potential to place further lives and properties at risk, police said.

The Walters Bluff bush fire on the outskirts of Nelson. Photo / Facebook

As part of their investigation, police want to identify and speak with three males seen on a bench on the Centre of New Zealand track in close proximity to Iwa Rd, around 1.30pm on Friday.

They are described as Caucasian and between 16 and 20 years old.

Two were possibly wearing baseball caps and one had fair hair.

This afternoon police will visit properties in the Iwa Rd area and neighbouring addresses looking for witnesses and gathering information from the public.

• Anyone with information on either fire should call police on 0800 08 02 09 or Crimestoppers on 0800 555 111 anonymously.

Rabbit Island fire

The Rabbit Island fire blazed over 10ha on Wednesday afternoon and people were asked to leave the island and nearby Rough Island immediately.

Fire and Emergency NZ (FENZ) were alerted to the fire about 2.30pm. Crews were sent from Nelson, Richmond and Brightwater.

Four ground crews and three aircraft had to be redirected from fighting the massive Pigeon Valley fire to deal with it.

The fire was said to have broken out at the popular recreation and beach reserve on the island.

It was brought under control by 8pm on Wednesday and managed overnight.

A community meeting was told today that it was "possibly deliberately lit", according to Civil Defence recovery manager Adrian Humphries.

Iwa Rd fire

On Friday afternoon, as firefighters battled the first fire at Pigeon Valley, a new fire broke out alarmingly close to the Nelson city centre on Walters Bluff about 3pm.

Five helicopters were in action on the hill and nearly 30 personnel from Canterbury councils were deployed to help respond.

The fire was said to have spread rapidly up a hill. Thirty-five residents self-evacuated.

Huge plumes of smoke could be seen across the city, roads were closed and cellphone coverage went down.

Some of the helicopters near the city fire were temporarily grounded after a drone was sighted, prompting officials to urge residents to "please stop" interfering with their operations.

Police confirmed that a 49-year-old man was arrested in the area on a disorder offence, but would not say whether it was related to the fire.