CAN green tea protect against breast cancer, bowel cancer and leukaemia? Australian researchers have been given almost $1million to find out.

The four-year study also hopes to identify the genetic make-up of people who are able to benefit most from certain chemicals, called polyphenols, which are present in green tea.

If successful, the study will add to a growing body of evidence linking green tea with health benefits such as weight loss, lower cholesterol levels and prevention of diabetes.

Professor D'Arcy Holman from the School of Population Health at the University of Western Australia said more than 70 laboratory and animal studies worldwide had consistently shown that green tea halts tumour cell growth.

This study hopes to find whether those anti-cancer effects translate to humans, particularly for breast, colorectal and blood cancers.

Raymond Mao imports six types of tea from China and serves them at My Tea House in Neutral Bay.

"I sit each customer down for five minutes and tell them which tea is good or not good for different conditions," he said. "It's a bit like wine tasting, but I do tea tasting."