A Sri Lankan mother-of-three will remain in indefinite detention after an independent reviewer upheld ASIO's assessment that she is a threat to national security.

While two refugees and their three children were released on Wednesday after the reviewer recommended that their adverse assessments be lifted, Ranjini is one of three refugees whose ASIO assessments were upheld.

The five cases are the first of 56 to be reviewed by retired judge Margaret Stone, who was appointed last October after the High Court struck down the regulation that prevented them from being granted protection visas.

''The fact that two out of the five got a positive result at this review says nothing about what the proportions might be in the future,'' Ms Stone told Fairfax Media.