A free online service has been launched to connect willing study participants with Australia's scientific institutes and universities.

The website aims to help researchers to find suitable volunteers to fill the rising number of clinical trials.

Founder Lucy Williams said that this will ease researchers from spending a considerable amount of time, effort and money trying to find people for their trials.

Recruiting adequate numbers of volunteers in a timely manner is a key factor in determining whether a trial will be completed on time or not.

In worst cases, she said, a lack of suitable study participants has forced scientists to send their research projects offshore.

Ms Williams said more than 700 trials were conducted every year, requiring an estimated 20,000 volunteers, for work that underpinned the development of new treatments and advanced the scientific understanding of the human body.

She said the web portal would allow research institutes to refocus their efforts on scientific discovery while Australians would have a new and central way to see what was on offer.

Researchers were looking for both healthy volunteers as well as those with specific illnesses, she said.

Current trials are open for people with asthma, spinal cord injury, dermatitis, sleep apnea, autism, diabetes, lung disease, obesity, multiple sclerosis, asperger's syndrome, knee osteoarthritis, dementia and kidney disease.

Ms Williams said trials were a way for people with health problems to gain early, and free, access to drugs or therapies which may be years away from mainstream availability.

Other trials include a Melbourne-based study into the health benefits of cocoa, a study into looking for a link between a woman's diet and bone density (Adelaide) and a trial of overcoming social phobias without the use of alcohol (Sydney).

Many Australians are unaware of the variety and number of interesting clinical research studies that they can participate in, Ms Williams said.

People can look at all the trials needing volunteers without having to sign up or commit to anything but if they are interested in a study then they can contact the researcher directly to get more information and ask questions.

Trial participants usually have their expenses reimbursed but Ms Williams said volunteers were usually motivated by gaining a greater awareness of their health and an overall feeling that they are helping to find a new treatment or a cure for a disease.

The website was officially opened to the public on Thursday.