KiwiSaver funds managed to overcome a series of local and foreign disasters - and some heavily negative market news - to perform strongly over the March quarter, Morningstar says.

The investment research company, in releasing its KiwiSaver performance survey, said share and fixed-income markets posted strong results, despite the February 22 Christchurch earthquake, the earthquake and tsunami in Japan, continuing uncertainties about debt levels in Europe, and reports that the United States would need to enter a third round of quantitative easing to bolster its flagging economy.

"It's therefore perhaps surprising that almost all asset classes enjoyed strong performance, which also flowed through to the performance of KiwiSaver funds," said Chris Douglas, Morningstar's co-head of fund research for Australasia.

All the main asset classes produced positive results for the first three months of 2011, continuing the solid showing in 2010, he said. The local sharemarket's NZX-50 index was up 3.95 per cent over the March quarter, although the New Zealand sharemarket lagged most of its global counterparts.

The Australian market produced a 6.66 per cent return over the three months to March 31. Global sharemarkets overall were up by 7.33 per cent over the same period.

While both domestic and global bond markets trailed sharemarkets, they still produced returns of 2.21 and 0.50 per cent respectively.

Global listed property, the best-performing sector last year, continued its performance run this year, up 9.14 per cent over the first three months.

The strong returns from sharemarkets resulted in KiwiSaver funds with higher exposures to growth assets (shares and property) outperforming those with more invested in income assets (cash and fixed income) over the March quarter.

Single-sector equities and multi-sector growth and aggressive options were the best performers over this year's first three months, again continuing the trend from last year.

Despite the continued strong market performance, last year's best-performing KiwiSaver funds were not necessarily the top performers for the March quarter.

ASB KiwiSaver, Fidelity KiwiSaver, Grosvenor KiwiSaver and Westpac KiwiSaver were the best-performing multi-sector options in the first three months of 2011.

"Looking out over three years is of course a better indicator of a fund manager's performance record. But there still are not any clear patterns, given the highly volatile performance period from April 1, 2008, to March 31, 2011," Douglas said.

The best-performing multi-sector fund had been Fisher Funds Growth KiwiSaver, well ahead of its peers over a three-year period in in which it gained 11.46 per cent, Douglas said.

Aon had the number two and three spots, with Aon KiwiSaver OnePath Balanced and Aon KiwiSaver Russell Lifepoints Conservative being the next best performers.

MorningStar said KiwiSaver assets on its database had growth at a phenomenal rate - from $954 million in June 2008 to $8.07 billion by last month.

OnePath and ASB remained the dominant players, with 45.0 per cent of KiwiSaver assets between them.