Melbourne researchers are hoping the tuberculosis (TB) vaccine may hold the key to preventing allergies in children.

The University of Melbourne, the Murdoch Children's Institute and the Mercy Hospital want to trial the vaccine to see if it helps boost immunity to protect them against allergic disease and infections.

The vaccine was routinely given until the 1980s in Australia, but was stopped after a decline in the number of people affected by TB.

Professor Nigel Curtis, from the University of Melbourne, says small studies have already shown positive results.

"It's actually not understood completely how the TB vaccine kick starts the immune system in this way," he said.

"There's plenty of evidence that it can do that from both small studies in humans and animal studies and the results from that did show reduced allergy in babies that had had BCG (the vaccine)."

Professor Curtis says the number of children who suffer from allergies has skyrocketed in the past 20 years.

The most common allergic diseases are eczema, food allergies, hay fever and asthma.

Professor Curtis says the reasons for the increase in numbers is not clear, but there are a few theories.

"We live in too clean an environment and we're not exposed to enough good bacteria and other germs early in life in the critical period when the immune system needs a kick start to train it," he said.

Researchers hope to get 1,400 children for the study, which will be carried out over a two-year period.

Half the babies will be given the vaccine and during study period researchers will monitor them to compare the rates of allergy and infection.