Marlborough's rural fire chief is warning people to be careful around the Wither Hills area, after three suspicious fires were lit yesterday.
A group of scrub fires broke out in quick succession near the Wither Hills Farm Park at about 2.30pm yesterday.
Police and the Fire Service are treating the fires as suspicious and linked to each other, but say it's too early to determine if they are linked to deliberately-lit fires in the area in March 2016.
Each of yesterday's three fires burned through an area of about five hectares.
Marlborough Rural Fire Authority principal officer Richard McNamara said, as fire fighters responded to the first blaze, the second blaze broke out, and then the third.
He said, luckily, the main helicopter provider was giving rides to youths at the National Scout Jamboree in nearby Omaka and flew into action.
"They saw the smoke and immediately swapped to firefighting mode, putting buckets on.
"They were very quick, they got there within 10 minutes."
The quick response enabled firefighters to bring each fire under control, and the fires were now all but extinguished, he said.
However Mr McNamara said there was no guarantee another fire could be put out so quickly, and the public needed to play its part in taking care with flammable materials in the area.
The second fire was lit near the Wither Hills mountain bike park, which could get about 27,000 visitors a year, and the third was lit near a new subdivision, he said.
While he had no way of "reading minds" to anticipate if there would be another deliberately-lit fire in the coming days, he said people needed to take care to avoid walking and biking tracks in the area in the middle of the day.
"We advise people to be very cautious when it comes to using the Wither Hills recreation facilities, particularly in the heat of the afternoon.
"Stay low on the slopes so your escape is always at hand.
"If you go high on the slopes and a fire gets going underneath you, with the smoke and the noise these things sound like 100 freight trains coming towards you."
Police are investigating the fires and want to hear from anyone who saw someone acting suspiciously in the area around or after 2.30pm.
A spokesman said they believe the person responsible arrived in a vehicle or on a bike.
Fire investigators remain at the scene today.
In October 2014, a fire in a pine plantation burned seven hectares before it was contained.