David Bain will not have to pay back legal aid with his earnings from interviews or any other money he might come into.
There has been speculation Mr Bain (37) may have been paid as much as $50,000 for his first interview following his acquittal last month after a three-month jury retrial. Mr Bain was found not guilty on June 5 of the deaths his five immediate family members at their Dunedin home in 1994.
A women's magazine this week published the first of two articles on Mr Bain, the first extensive interview he has given since his family's deaths.
A Legal Services Agency spokeswoman confirmed Mr Bain would not have to repay his legal aid because under the Legal Services Act any changes to a person's financial situation once a matter has been concluded cannot be taken into account retrospectively.
In the 2007-8 financial year, about one quarter of the people who received legal aid were asked to repay some or all of it.
An assessment of a person's ability to make repayments was made at the time legal aid was granted.
The assessment was made taking into account any income and assets and the thresholds set down in schedules to the Legal Services Act.
A repayment schedule was not put in place for Mr Bain at the time he was granted legal aid so he would not be required to make any repayments, the spokeswoman said.