The Cook Islands Court of Appeal has found the law establishing a compulsory Superannuation Fund is valid.
The government was appealing a High Court decision which found the National Superannuation Act of 2000 was unconstitutional, as it went too far in restricting people's enjoyment of their property rights.
The Court of Appeal found that the limitations imposed by the Act were outweighed by significant benefits.
It said the Act promoted the general welfare of Cook Islands people and was justified under the Constitution.
But the court said the respondent's arguments had merit, and raised questions of public importance.
It says it hopes the case might lead to the government conducting a formal review of the Act, to find out whether any amendments are needed.