Rally New Zealand organisers are working to determine the cause of a fire which destroyed the car of two Swedish motorracing drivers last night.

Competitors Ramona Karlsson and co-driver Miriam Walfridsson were lucky to escape significant injury after their Mitsubishi Lancer Evo X caught fire mid-race.

Emergency services were called to the blaze on the outskirts of Tangihua Forest near Dargaville just before 5.30pm last night.

The women were treated for minor burns but their car was gutted by the fire.

The car did not crash, and organisers are working to determine the cause of the freak accident, rally spokesman Lance Hastie said.

It was the Swedish tourists first time racing in New Zealand and they were just hoping to finish the race, Hastie said.

''They were doing OK amongst a field of very experienced competitors, their goal was just to finish.

''They were hoping for a placing in the production category but more importantly wanted to finish.''

A driver close behind them contacted emergency services and the car's GPS system alerted organisers that they had stopped.

''They sustained superficial burns, battle scars as they got out of the burning car,'' Hastie said.

''There wasn't really a lot of time for them to get out, the priority was for their own safety.''

They were 4km into Northland's stage of the race when their pink Mitsubishi Lancer caught fire, with flames spotted up to 60m above the forest canopy, the Herald on Sunday reported.

There were initial concerns that the forest was in danger but the fire was quickly contained.

The women are back on the field today, but this time as spectators, Hastie said.

''They're fine, they're in high spirits, that's the main thing.''

- © Fairfax NZ News