The Fianna Fáil leader says the Garda Commissioner needs to comprehensively deal with the controversy surrounding the O'Higgins Commission report.

Micheál Martin says there's a 'daily reality of leaking transcripts' and Nóirín O'Sullivan must explain the instructions she gave her lawyers on how to treat garda whistleblower Sergeant Maurice McCabe.

The issue has dominated the Dáil again today, with Tánaiste and Justice Minister Frances Fitzgerald stating she expects the Commissioner will deal with the controversy.

This evening Micheál Martin re-iterated that the Commissioner must answer questions, though he is not looking for her resignation.

"I have confidence in the Garda Commissioner," he explained. "But I do think that the issues are important, because they do as I said cut to the core of a culture that suppresses whistleblowers".

In the Dáil this morning, the Tánaiste says she expects the Garda Commissioner to clarify as many issues as she can.

It was reported last week that documents from the O'Higgins Commission of Inquiry suggested the Garda Commissioner claimed the whistleblower was "motivated by malice".

Sargeant McCabe is said to have presented the Commission with a tape of the meeting in question that disproved the allegations, and no mention of the comments featured in the final report.

In a statement earlier this week, Ms O'Sullivan said she is legally barred from clarifying certain matters related to the Commission.

She apologised to victims who she said believed "with justification" that they were not dealt with properly by the force, saying gardaí will "seek to work with them".

She added: "Like every member of An Garda Síochána, Sergeant Maurice McCabe’s contribution is valued and the service has changed for the better in response to the issues about which he complained. I want to make it clear that I do not - and have never, regarded Sergeant McCabe as malicious".