SYDNEY: The Australian and New Zealand dollars rose on Wednesday as their US counterpart remained locked in a downtrend, while investors wagered the widening rollout of vaccines would bolster global growth and commodities next year.

The kiwi dollar climbed to $0.7176, reaching its highest point since April 2018. That was up from a $0.7085 low early in the week and another step toward a major chart target at $0.7395.

The Aussie firmed to $0.7631, again up from a $0.7559 low touched at the start of the week. The next big barriers were the recent 2-1/2 year top of $0.7639 and then $0.7677.

It was also faring well against the Japanese yen, having reached its highest since April 2019 at 78.94 yen.

Part of the gains were due to broad-based weakness in the safe-haven US dollar as the market bets on better times in ahead and more debt-funded US stimulus.

"The start of Covid-19 immunization campaigns in several countries as well as additional US fiscal support reduce downside risk to the global economy and bode well for general financial market sentiment," said Elias Haddad, senior currency strategist at CBA.

The decline in the US dollar is lifting prices for many commodities priced in the currency, supporting earnings from resource exports out of Australia and New Zealand.

Australia's earnings from iron ore alone climbed to a record high of A$139 billion ($105.95 billion) in the year to November, and prices have risen further since then.

One looming threat at home was a growing outbreak of coronavirus in Sydney, with more cases being reported on Wednesday and outside the initial cluster.

The state government announced tighter social restrictions for New Year's Eve but the risk was for a broader lockdown across Australia's biggest city.