Finance Minister Bill English says a review of the Overseas Investment Act has not been able to go as far as he expected.
The Government announced the review a year ago with the aim of attracting more foreign investment.
It wanted to simplify the act and clear up confusion caused by the previous Government's strategic interest test.
The test was designed to block the sale of Auckland International Airport Ltd in 2008.
It was criticised by the National Party for not defining what was a strategic asset.
Mr English says a national interest test that is still to be released, will not give an exhaustive definition either.
But he says he is confident a lack of clearly defined rules will not deter foreign investment.
