"There is clear evidence that rabbit populations have begun to recover from calicivirus in the past three-years," Mr Mutze said.

There are four reasons behind the recovery in rabbit populations:

• Genetic resistance in wild rabbits.

• The released calicivirus has undergone some mild genetic changes.

• Widespread winter-spring droughts have slowed the disease uptake more than they've slowed the reproductive output of rabbits.

• Another benign strain of calicivirus has been identified in rabbits.

"We had suspected that this Rabbit Calicivirus Australia1 virus has been here for a while," Mr Mutze said.

"It has probably been a significant factor on the low impact of calicivirus in wetter areas.

"But we don't know the areas where this RCA1 is common.

"We don't know if it is becoming more common."

He said there were no research programs looking at alternatives to calicivirus or myxomatosis at the moment.

Introducing another disease to control rabbits would take at least 10 years to trial and research - and it would cost $20 million to look at such a program.

"While the process with introducing a new strain of calicivirus would be similar, as we already have the calicivirus disease here, so it would take about three-years to test," Mr Mutze said.

The Invasive Animal Cooperative Research Centre will find out in late June or early July if it has been successful in its bid to test another strain of calicivirus.

Only one strain of calicivirus, the Czech strain CZ351, was introduced to Australia in 1995.

Rabbit Eradication committee member Barry Barratt said landholders and the SA Pest Animal & Plant Control Board needed to control rabbits on properties as the first line of defence.

"There is no point in bringing out a new virus if people are not using control methods on-farm," he said.

"I haven't seen a property where rabbits couldn't be controlled by ripping, using dogs and fumigating."