SYDNEY — Resources-rich Australia has signed on to provide Japanese households and industries a reliable source of natural gas for decades to come.

As this country's biggest, most respected market for resources, Japan is first up for gas supplies from a newly approved undersea gas field off Western Australia called Gorgon. Construction on the multinational project starts within weeks, and decades-worth of shipments are already being sold, with more oil and gas fields still to be developed.

Six sales contracts worth hundreds of billions of dollars have been inked in recent weeks with Asian countries. Estimates of revenue from the bonanza stagger Canberra, where the Rudd Government is already hell-bent on an anti-recession spending spree.