Trials on domestic rabbits have shown the ''95 Mackenzie Basin'' strain killed 100% in a mean time of 39.9 hours.
Six of the nine strains tested - Wanaka, Luggate, Hawkes Bay, Hawarden North, 322 Mackenzie Basin and Lincoln - were also 100% effective on domestic rabbits, but took longer to cause death.
The least effective was the Alexandra strain which killed 80% of domestic rabbits and the ''time to death'' was 125.6 hours.
The original Czech strain, introduced illegally from Australia in 1997, killed 88% of rabbits in a mean time of 74.3 hours.
The research is being carried out by Lincoln-based Dr Janine Duckworth, leader of Landcare's rabbit biocontrol initiative.
She told the Otago Daily Times yesterday each of the strains was tested on eight domestic white rabbits.
The aim was to find a strain that killed ''quickly and humanely''.
While 24 strains of RHD had been detected by her team, only nine were tested because of resource limitations.
The next step, over the next year, would be to test different strains on wild rabbits, although that would be more difficult because the rabbits' history, particularly their previous contact with RHD, would be unknown.
Dr Duckworth said when rabbits were originally introduced from England they had some antibody resistance to the disease, and rabbits had also built up varying levels of resistance to the new strains over the past 18 years ago.
Knowledge of resistance levels was already playing a part in rabbit control programmes.
It was known young rabbits had more RHD resistance, so it was less effective to release the virus when there were a lot of young rabbits.
She said regulatory approval might be needed to use the Mackenzie strain in other areas.
