Australia's Prime Minister Kevin Rudd said the guarantee would be for the next three years.
The government of New Zealand has offered a two-year guarantee.
Meanwhile, the head of the International Monetary Fund has said the world's financial system is on the brink of meltdown.
However, Dominique Strauss-Kahn has said he hopes the G7 plan, discussed in Washington last week, would safeguard the long-term future of banks.
