Milford's Active Growth fund is the best performer over five years in the growth category with an average annual return of 15.2 per cent.
Chris Douglas, director manager research ratings at Morningstar, said the first half of 2017 saw KiwiSaver funds with a bias to growth assets perform better than more defensive conservative funds.
Growth funds have a higher percentage invested in shares and listed property assets.
Douglas said the New Zealand share market had performed slightly better in the second
quarter of the year than it did in the first and the NZX50 index was up 5.8 per cent over the quarter.
But the Australian sharemarket had not done as well only rising 3.2 per cent since the start of the year.
"New Zealand investors had the benefit of a small depreciation of the New Zealand dollar against the Australian dollar over the half year, giving them a total return of 4.1 per cent in New Zealand dollar terms."
The MSCI world index was up 8.2 per cent in the first half of the year in local currency terms.
KiwiSaver now has more than $40.5 billion invested and ANZ remains the biggest provider with $10.4b in funds under management.
The full report can be seen here.