He said New Zealand managers also faced headwinds in Australia.
"New Zealand managers are small players in the Australian equity market, due to the relatively small pool of funds available for investment from New Zealand investors.
"The resources available to New Zealand-based managers are also constrained by the size of the funds under management."
Schiltknecht said these factors did not mean New Zealand fund managers were not competitive stock pickers in Australia and, in fact, the research showed New Zealand managers had done a relatively good job.
But he said managers should address the headwinds and justify why they were investing in Australia.
"We are not advocating against transtasman portfolios but investors need to be aware of the risks. There needs to be more transparency around performance."
Schiltknecht said that managers needed to separate out their New Zealand and Australian stock selection processes and decide how much of their money was going to be invested in Australia.
Fund managers had the ability to invest up to 100 per cent of their fund in Australian shares, he said, and some retail investors might not be aware of that.