The fire has had a serious impact on red grouse numbers

It is estimated that the cost of dealing with the damage on the Blorenge mountain, near Blaenavon, could be £100,000.

But the environmental cost of the loss of wildlife and rare plants means the area could take decades to recover.

The fire, on a site of special scientific interest, has been blamed on arsonists.

This isn't killing the golden goose, it's burning the golden goose Julian Branscombe, Gwent Wildlife Trust

The mountain is one of the two most important habitats for the red grouse in south Wales.

The fire took hold during the egg-hatching season and Gwent Wildlife Trust fears that 15 of the estimated 20 breeding pairs could have been lost, and much of the grouses' moorland habitat has also been destroyed.

A road had to be closed after the first outbreak on 24 May

Julian Branscombe, chief executive of Gwent Wildlife Trust, said: "It could be years before the habitat recovers, it's quite catastrophic because of the importance of the site and the longevity of the impact.

"Moorland is managed so fire can be used in a controlled way, burnt off in strips to help conserve the grouse's habitat but the way the fire took hold and the effect on plantlife, it could last for 20 years."

"Half the red grouses' habitat has been lost so far and it's had a devastating effect on an environment that is already existing on a knife-edge."

Wildlife and plantlife ranging from skylarks, adders and crowberries have also suffered, as well as insects.

The fire first broke out on 24 May and up to 70 firefighters were called out.

Winds picking up on the exposed moorland can reignite the flames

The terrain means that firefighters have to walk 25 minutes from their vehicles to reach the fire.

Open to the elements, hot-spots re-ignite and crews have been forced to return to the scene on most days.

South Wales Fire Service estimate that the first three days, when the blaze was at its height, cost more than £91,000.

Firefighters report finding burnt nests, as well as dead snakes and slow worms.

Assistant divisional officer Roger Price said: "Fire crews who are fighting fires which have been started deliberately may be delayed in attending genuine emergencies such as house fires and road traffic accidents."

The fire service, Forestry Commission and Countryside Council for Wales - who manage SSSIs - have already met and there are plans to bring in an action plan and set up a joint response team.