A 400sq m bush blaze is burning beside a rural road near Ashburton.

A Southern Fire Service spokesman said three fire crews, four tankers and a digger were fighting the fire which has engulfed tree stumps and logs near Mayfield.

The blaze, which began about 6.30pm, was the result of a tree felling operation along Tanks Rd, the spokesman said.

He said the digger was helping move the tree stumps and logs to help firefighters properly extinguish the fire.