But the nation still lags behind other developed countries in sustainable tuna consumption.

The Safcol brand of tinned tuna has become the first well-known tuna brand to be ranked ''good'' under the international Greenpeace ranking system.

It climbed the rankings because of a recent decision to switch to a pole-and-line fishing method, which spares the sharks and turtles that are otherwise caught and killed in tuna nets, along with the policy that it only catches skipjack, the least-threatened tuna species.

One other brand, Fish-4-Ever, also scored a ranking of ''good'' but it is less widely available in Australia and more expensive than most other canned tuna because of a policy of returning fishing profits to local communities.

In Greenpeace's order from best-performing to worst in sustainable tuna fishing, the remainder of the commonly available brands are Coles, John West, Greenseas, Ocean Rise, IGA, Sirena, Woolworths and Sole Mare. Unlike Australia, in Britain all major canned tuna brands are assessed as ''good'' after a series of public campaigns to promote sustainable fishing.

''We'd like to see sustainable tuna available to every Australian who wants to buy it,'' a Greenpeace campaigner, Nathaniel Pelle, said. ''It's shocking that Australia is right on the Pacific, where most of the fishing actually goes on, yet we are well behind some other countries like the UK.''

The rankings are based on the region the fish is obtained from, which species of tuna are caught and the method used to catch them. The information was uncovered by tracing the code numbers and dates on individual cans back to canneries, and then back to the fishing fleets and voyages that netted a particular catch. Greenpeace's ratings are being launched this morning at Sydney Aquarium.

The other main sustainable fishing rating organisation operating in Australia, the Marine Stewardship Council, provides standards that fishing companies can be measured against, in a pass-fail system.

Its Pacific fisheries manage, Bill Holden, said the best reference was the International Seafood Sustainability Foundation.