As per the finding of an online survey led by RMIT University doctoral student Alicia Mitic, the Australian have a "vague" understanding of contraception or about related infections.
Most of the people surveyed said that a condom was their primary form of contraception, but half of them admitted not using it every time they had sex.
Among women who reported relying on oral contraceptives, 12 percent said that they accidentally missed a pill at least once a month.
"Few respondents understood the 'nitty gritty' details of the contraceptives they used, such as failure rates and potential side-effects," News.com.au quoted Mitic as saying.
"A big concern is that even though most people were using some form of contraception - primarily condoms or the Pill - few were using them correctly, increasing their risk of unwanted pregnancy and sexually transmitted infections (STI).
"They also had very little knowledge of the wide range of contraceptives available - many had never even heard of some of the options that were listed in the survey such as injections, implants, IUDs (intra uterine device) or natural family planning methods," she added.
The online survey, which will remain open until February, is designed to probe the contraceptive practices, knowledge, attitudes and decision-making of Australians aged over 18, and it has received responses from almost 600 people so far.
Further early findings include 40 per cent of respondents had never undergone a test for STIs, while 14 per cent had been previously diagnosed with an STI - usually genital warts, herpes or chlamydia.
Three per cent admitted to lying to a partner about their STI status, while 17 per cent were "unsure'' of their partner's STI status.
More than a third of respondents said that they had experienced negative side-effects related to contraceptives. (ANI)