RABBIT numbers are on the increase this summer due to high rainfall and strong pasture growth across Victoria.

Department of Primary Industries biosecurity manager for established invasive animals John Matthews said data indicated rabbit numbers were starting to rise from a 15-year low.

He said analysis of the 2011 spring program indicated an increase in both population and active warrens.

"Recent high rainfall and strong pasture growth will also improve survival and extend the breeding season," he said.

The DPI rabbit monitoring program covers 17 sites on farmland including Manangatang, Beechworth, Harcourt, Yambuk and Swifts Creek, and has been running since 1998.

"It appears a high proportion of rabbits have antibodies to the biological control agent rabbit haemorrhagic disease (RHDV), released in 1995-96," Mr Matthews said.

"This is evident across all sites with around half the kittens, 70 per cent of young adults and 80 per cent of older adult rabbits moving into the next breeding cycle, having antibodies to RHDV and would likely survive further exposure to the disease."

He said a positive note was that there had been a sustained reduction in rabbit populations where broad scale destruction of warrens had taken place.

Mr Matthews said landholders need to start control programs, like ripping up warrens, during summer while rabbit numbers were low.