Firefighters are battling three "pockets of fire" near Blenheim this afternoon.
Fire Service southern communication shift manager Brent Dunn said the blazes being treated as suspicious and a rural fire investigator would likely investigate the cause of the blaze.
A spokeswoman for police was unable to confirm whether police would help with the investigation.
Police have advised locals and motorists to avoid the Wither Hills Farm Park, where emergency services were called about 2.30pm.
A Fire Service spokesman said three helicopters had joined crews from the Rural Fire Authority and the Fire Service.
He said there were three fires south of Blenheim, all fairly close together. One was on Taylor Pass Rd near the landfill, the other two around the Maxwell Pass.
"They're all being treated as one job," Dunn said.
The world-famous Wither Hills winery was not threatened.
"It's very dry down there," the spokesman said.