Friends of Whyalla Conservation Park member president Clint Garrett said rabbits have cost the economy more than $200 million a year in lost production, not including the damage to the environment.

Rabbits have significantly reduced native flora and fauna in Australia, including Whyalla's surrounding scrublands.

Mr Garrett, who is also a member of the Australian Campaign for Rabbit Eradication said although it was much worse in other areas, Whyalla was still trying to stop the pests by using explosives and gas bombs in rabbit burrows.

"Because their damage is a little bit here, and a little bit there, people tend not to notice," Mr Garrett said.

"But add it up over a year and they remove many kilos of plant material."

He said the most important issue was the damage they caused by eating seedlings.

"Rabbits love young myall and black oak seedling," Mr Garrett said.

He said the result would mean no replacement trees for older trees as they die, which results in fewer trees in the landscape.

Damage can be seen on plant stems or tree bark which has been chewed, or areas where all plants have been chewed or eaten away.

Rabbits also remove biomass, which soaks carbon dioxide.

A study showed that rabbits could eat up to 1.4 million seedlings per square kilometre.

This meant Opposition Leader Tony Abbott's plan to plant 20 million trees to offset carbon dioxide output would be pointless.

Mr Garrett said when calici virus was released it helped for some time.

But now rabbits are developing a stronger immune system against the virus, which has called for stronger action.

Mr Garrett encouraged people to take part in a national initiative called RabbitScan.

RabbitScan gets anyone involved in monitoring their town or city's surroundings that could be affected by rabbits, by uploading the information to www.rabbitscan.net.au.

"I would encourage people to find an area near Whyalla and give it a try, they will be doing something good for the environment and getting some exercise too," Mr Garrett said.

The data will help build a national map of rabbits and their threats to Australia's bio diversity and productivity.