Three more regions are to get on-the-spot syphilis tests in the ongoing fight against the potentially deadly outbreak in northern Australia.

The quick tests are now available in East Arnhem Land and Katherine in the Northern Territory and the Kimberley in Western Australia.

They became available in northern Queensland and Darwin in August.

Indigenous Health Minister Ken Wyatt said feedback from Queensland and Darwin was that the tests were having a positive impact.

"Since the syphilis outbreak started in 2011, there have been more than 2200 reported cases," Mr Wyatt said. "This is a preventable disease, and in this day and age, it's a tragedy that it is so prevalent in some First Nation communities."

The Federal Government is spending $8.8 million to curb the outbreak of syphilis in Aboriginal and Torres Strait Islander communities.

The on-the-spot tests allow instant diagnosis and if needed, immediate treatment.

"Previously, results from traditional blood tests could take up to two weeks to be processed, which caused issues with people moving on before receiving treatment and potentially spreading the disease," Mr Wyatt said.

The Royal Australasian College of Physicians warned earlier this year that northern Australia was in the middle of the worst outbreak of syphilis in three decades.

A number of babies whose mothers became infected or who were infected have died as a result of the outbreak.

By Wendy Caccetta