Investigations are complete into the cost of a mammoth fire in the South Island, which incinerated more than 330 hectares of land.

The Flock Hill blaze was among the biggest fires to sweep across wilding pines and grasslands at the start of this year.

Department of Conservation fire technical support officer Craig Alexander can't say how much money went to waste as a result of the destruction ... as there are legal processes pending.

He says it's unknown at this stage whether a party will be held responsible for the fire.