Analysts say stronger confidence in soft commodities has prompted a preference among global investors for New Zealand's stock market rather than Australia's.
The benchmark Australian ASX200 index has risen 11% so far this year while the NZX 50 index has jumped 19%.
Milford Asset Management executive director Brian Gaynor says countries like New Zealand, which produce soft commodities like dairy products, are viewed as being in a better position than and other nations that produce hard commodities, such as iron ore.
He says the Chinese government is trying to move from being an infrastructure investment economy to one led by consumer spending, and this benefits New Zealand and disadvantages Australia.
Mr Gaynor says overseas investors see New Zealand as relatively more attractive, which is reflected in the strength of New Zealand dollar against the Australian currency.
Tower Investments chief executive Sam Stubbs says the preference shown for the New Zealand stock exchange could falter after last weeks move by Reserve Bank of Australia to cut interest rates to a three-year low.
Mr Stubbs says that will make the Australian stock market relatively more attractive for investors and for those people who are choosing shares over bonds or fixed interest investments.