Rates of sexually transmitted infection will soar in Queensland following the slashing of services at Brisbane's only free sexual health clinic, a doctor has warned.

HIV specialist Wendell Rosevear said a decision to cut up to 30 jobs at Biala clinic was a purely economic one that did not consider the state's health needs.

"The sexual health service is very needed and is a cost saving service," Dr Rosevear said.

"If young people don't treat chlamydia, it ends up costing the health system more with infertility.

"Gonorrhea and syphilis rates are also rising, so we can't afford to have less access to medical care."