"If that trend continued, why would people still trade their assets on the New Zealand exchange? It is a matter of stepping up the game and making sure the NZX is competitive."
Frijns' research found the issue was more pronounced for New Zealand's biggest listed companies. In 2001, 87 per cent of Fletcher Building's price discovery came from the NZX. Last year that had shrunk to just 21 per cent.
For Telecom it was even higher, shrinking from 87 per cent in 1998 to 9 per cent in 2012.
Telecom, Fletcher Building and Trade Me are the most traded New Zealand companies on the ASX this year.
Smaller dual-listed New Zealand companies such as New Zealand Oil and Gas were still New Zealand dominated, although its price discovery had slipped from 88 per cent in 1998 to 69 per cent last year.
Frijns said New Zealand needed to maintain its local exchange because it was important to have a place for new companies and start-ups to list.
But it needed to become more competitive.
"I don't think you can stop companies dual-listing. This is competition between the exchanges."
On Wednesday, NZX boss Tim Bennett said he was not concerned about the ASX coming down to New Zealand and that on average 90 per cent of the trades for dual-listed companies still came via the local exchange.
"What we find is that unless you are large or have an Australian business, like Kathmandu, you actually don't get a lot of interest from brokers and don't get a lot of liquidity. They are certainly not taking a lot of liquidity from us."