Fianna Fáil's Justice Spokesman says he's '100 per cent certain' he told Frances Fitzgerald about Tusla's role in the whistleblower saga last WEDNESDAY.

Jim O'Callaghan's contradiction of the Tanaiste comes as his party leader called on the Garda Commissioner Noirin O'Sullivan to 'assess her position'.

Frances Fitzgerald is sticking to her position that she knew nothing of Tusla's role in passing on damaging and baseless allegations about Maurice McCabe, before Prime Time on Thursday.

But Jim O'CAllaghan says that's simply not true. He's going on the record to state with absolute certainty that he TOLD Fitzgerald about Tusla's role, and the forthcoming TV bombshells, 24 hours earlier.

That would cast doubt over the Tánaiste's account to the Dáil last week.

Meanwhile FIanna Fáil has increased the pressure on the Garda Commissioner NOirin OSullivan, who intends to remain in place despite being investigatead by the new Charleton Commission.

This morning Micheal Martin told local radio in Cork that she should "assess where she stands" - and wouldn't be drawn on his support.