One-fifth of young Australians aren't following through with chlamydia testing, prompting researchers to call for clinics to take action.

One in five young Australians are not submitting a specimen for chlamydia testing after a request from their GP, new research says.

Those most likely not to follow through are men, people aged 16 to 19, those living in socioeconomic disadvantage and those attending clinics without on-site pathology collection.

But younger age and socioeconomic disadvantage are the key risk factors for the sexually transmitted infection, say the study's authors, of the University of Melbourne, Monash University, the Alfred Hospital and the Kirby Institute at the University of NSW.

If left untreated in females, chlamydia could lead to pelvic inflammatory disease causing chronic pelvic pain and even infertility.

In males it can lead to longer-term infection of the testicles.

"Guidelines recommend that sexually active men and women aged 15-29 years have an annual chlamydia test, but less than 10 per cent of this age group are screened each year in general practice," the study authors say in the Medical Journal of Australia.

The study related to a chlamydia testing intervention program for 16-29 year old at GP clinics in a number of Australian towns and Melbourne in 2013.

There were 13,225 chlamydia test requests, of which 2545 did not take place.

The authors say the reasons might involve embarrassment or concerns about confidentiality and privacy at GP clinics.

"It has been argued that simply raising awareness about the risk of chlamydia may not increase testing, and that providing reassurance of non-infection may be more productive," they say.

The odds of not taking a test are 40 per cent higher in clinics without on-site pathology collection.

The authors suggest the uptake of testing might rise if patients could leave self-collected specimens at the clinic, which could then be couriered to the pathology provider.

Clinics need to set up systems to ensure tests ordered by GPS are actually undertaken, they say.