The New Zealand dollar has hit its highest level against the greenback in just over three years.

The kiwi peaked at 81.23 US cents, its highest level since March 2008, before paring back to just over the 81 cents mark.

The move followed a report by that China's sovereign wealth fund may be looking to boost its purchase of local assets.

The website said China Investment Corp. had set aside $6 billion or 1.5 per cent of the total fund to invest in local assets, including stocks, bonds, and other assets.

It didn't identify the source of the information.

The move above 80 U.S. cents was helped by positive performance by US stocks, with the Standard & Poor's 500 Index gaining 0.4 per cent to 1,326.33 after jeweller Tiffany & Co. raised its earnings forecast.

That helped buoy investors' appetite for risk, and spurred demand for growth-linked currencies such as the New Zealand and Australian dollar.

"A lot of people are reluctant to start shorting the kiwi because on the demand side we still have insurance flows, high commodity prices mean there is ongoing exporter demand, and there is solid demand for government bonds," said Khoon Goh, head of market economics & strategy at ANZ New Zealand.

The kiwi dollar recently traded at 81.09 US cents, up from 80.77cents yesterday, and rose to 70.36 on the trade-weighted index of major trading partners' currencies from 70.18 yesterday.

It was little changed at 76.22 Australian cents from 76.18 cents previously, and fell to 65.95 yen from 66.15 yen.

It climbed to 57.36 euro cents from 56.96 cents yesterday, and fell to 49.47 pence from 49.58 previously.

The kiwi dollar may trade between 80 US cents and 81.20 cents, Goh said, with the currency likely to move higher next week if it is able to sustain these levels into the offshore session.