A stack of wooden pallets found burning outside an Invercargill home around midnight is being treated as suspicious.

Fire and Emergency New Zealand shift manager Andrew Norris said one crew attended what was initially thought to be a bush fire on Tanner Street.

However, when the crew arrived around a quarter past midnight today, they found a stack of pallets on fire outside the vacant home, causing external damage.

Mr Norris said the fire was being treated suspiciously, although the owner was known to have a history of burning materials in the back of the property.