The Australian dollar is a third of a US cent higher after encouraging jobs data from the United States pushed world markets higher.
At 0700 AEDT on Monday, the Australian dollar was trading at 104.72 US cents, up from 104.43 US cents on Friday.
Westpac New Zealand senior market strategist Imre Speizer said the currency moved higher on Friday night following the release of US non-farm payrolls figures.
The figures showed 155,000 jobs were added to the US economy in December, with the unemployment rate steady at 7.8 per cent.
"It was slightly better than expected and boosted risk markets," Mr Speizer said.
The figures helped push global share markets higher, with New York's S&P 500 climbing 0.49 per cent to 1466.47, its highest close since December 2007.
The Australian dollar has also hit a fresh four-year high against the Japanese yen.
At 0700 AEDT the Australian dollar was trading at 92.31 yen, just down from its early level of 92.49 yen, its highest level since September 2008.
Mr Speizer said the major local event for the currency this week would be Wednesday's release of Australian retail sales figures for November.
But he said concerns about an upcoming political fight in the US over the country's debt ceiling and speculation the Federal Reserve might end its stimulus program sooner than expected could weigh on the Australian dollar.
The US has reached its debt ceiling, meaning Congress will need to increase the limit the government can borrow within about six weeks to prevent the country defaulting on its bills.