The Public Accounts Committee is to write to the Rehab organisation, the HSE and the Department of Justice about operations at the charity.
It follows a storm of controversy surrounding comments in the Dail from the Justice Minister.
Alan Shatter was defending his decision to end the charitable lotteries scheme when he made his comments about Rehab on Tuesday night.
He revealed an investigation had found it earned less than €10,000 profit on scratch card sales of almost €4m in 2010. Rehab reacted furiously and demanded the Minister withdraw the comments and apologise.
The Public Accounts Committee was already planning to call Rehab to appear before it, and is now planning to write to the organisation, the HSE and Department of Justice about the latest details.
Meanwhile, a Rehab director has described as "an embarrassing oversight", a situation where he billed the charity for consulting services in 2011 and 2012 using a company that was dissolved in January 2009.
The charity was invoiced for €77,000 over the two years using Laragh Consulting Limited, a company that had an address in Finglas on Dublin's northside.
Frank Flannery, who is also a senior Fine Gael adviser, has told the Irish Times that the company was used for "a bit of private business", and he's now trying to get it restored to the companies register.