Kylie Kwong at her restaurant Billy Kwongs.
New course: Kwong has long endorsed a ''wholistic'' approach. Photo: James Brickwood

Award-winning chef Kylie Kwong has joined other ''hatted'' Sydney restaurateurs in backing the first international ratings system that ranks eateries based on their environmental, ethical and social impact.

The Sustainable Restaurant Association system, launched globally this week after three years running in Britain, allows diners to compare restaurants based on where they source their food, how they manage their energy, waste and water, and even how they treat their staff.

The not-for-profit organisation also advises member restaurants on how to become more sustainable and ethical.

Kwong says she has already inquired about signing up her one-hat Surry Hills restaurant, endorsing the scheme's ''wholistic'' approach. Since 2005, Billy Kwong has used locally grown, organic and biodynamic food - even the soy sauces, sugar, vinegar and oils are organic - and Fair Trade tea and chocolate. The restaurant also buys renewable energy credits from a wind farm in Hebei, China.

''If only I had someone like this seven or eight years ago when I shifted the menu from conventional to organic and local and biodynamic. It's taken me a long time to find a balance in my menu to get my food costs right,'' she said.

Other Sydney restaurants that have backed the global system include two-hat restaurant Biota Dining in Bowral and one-hat restaurants Sixpenny in Stanmore and Three Blue Ducks in Bronte. In Melbourne, three-hat restaurant Vue de Monde and the award-winning, zero-waste cafe Silo By Joost have also expressed interest.

About 500 British restaurants have completed the SRA assessment since the system began in 2010, including two Michelin star restaurants Le Manoir aux Quat'Saisons near Oxford, Andrew Fairlie at Gleneagles and The Ledbury in Notting Hill.

Lisa Margan, chef and restaurateur at Margan Wines in the Hunter Valley, said she would ''fully support'' an international certification program that was rigorous and thorough.

''The challenge in the past has been that no one knew where to start or how to go about it … There's still confusion about what sustainability means.''

Margan Wines is currently certified under two different programs - Restaurant & Catering's Green Table program and EntWine, offered by the Winemakers' Federation of Australia. Margan restaurant achieved its Green Table certification after completing an online questionnaire. Entwine, which incorporates international standards for environmental management practices, involved a “stringent” on-site assessment, Margan said.

“It took us one whole year to get certification, including going through a three-day on-site audit,” she said.

“There are some certifications that don’t require any on-site audit and that leaves the process open to interpretation or probably the better word is ‘exploitation’.”

More than 300 businesses, including about 100 restaurants, are certified with the Green Table program. But not everyone has welcomed the global system.

John Hart, chief executive officer of Restaurant and Catering Australia, said a global rating system was unnecessary, given that Australian restaurants could already sign up for certification through the Green Table program.

''I've looked at the Sustainable Restaurant Association stuff and I don't think it's got the integrity that our scheme has,'' he said.

Hart also questioned the usefulness of sourcing and societal components in the global rating system, saying the link between environmental impact and food sourcing was ''spurious''. The Green Table program focuses exclusively on reducing environmental impact through energy saving, water saving, recycling and sustainable waste practices.

“They might be lovely, feel-good factors and they might be buzz words for consumers but I would really question the impact they have on the business’s environmental footprint.”

Kwong the best way restaurants could serve the community was by offering them the healthiest, most sustainable food possible.

“[The Sustainable Restaurant Association has] a wholistic view of the industry and I couldn't agree with it more,” Kwong said.

“Restaurateurs and foodies are very influential people – especially in Australia because we’re all so obsessed with food … It’s almost our social responsibility and duty of care to send out the right messages and that includes sourcing produce that is ethical and sustainable.”