Australia's top central banker said on Tuesday that upside risks to inflation may be materialising given energy prices have stayed high and there continued to be excess demand at home, underlining market wagers for a rate hike as soon as next week. Speaking at a business lunch, Reserve Bank of Australia Governor Michele Bullock also said that unemployment in a range of 4.5% to 5.0% could help restrain inflation, suggesting some rise might be needed from the current level of 4.5%. Bullock said she was not trying to signal what might happen to rates when the nine-member RBA policy board met on September 29, but rather highlighting the upside risks to inflation.