Taoiseach Micheál Martin said that Leo Varadkar's decision to share a confidential document about a GP contract was not "appropriate".
The Tánaiste has been accused of leaking documents relating to an agreement reached between the Department of Health, the HSE and the Irish Medical Organisation (IMO) to rival organisation the National Association of General Practitioners (NAGP).
Mr Martin said that Mr Varadkar accepts it was "not best practice".
"This was not the appropriate way to deal with a document of this kind in terms of the manner in which it was sent to the (former) president of the NAGP," the Taoiseach said on Monday.
"My own view generally on an agreement of this kind is that, given the amount of public money involved, this should have been public knowledge much earlier.
"These agreements are not your normal type of a contract in terms of a commercial contract but rather it relates to the public health service and the expenditure of the health service. It should have been made public much earlier.
"In hindsight, that's the lesson to be learned from this."
Speaking at Government Buildings in Dublin, Mr Martin said that no one made any financial gain over the sharing of the document.
"There was no material advantage to any person," he added.
Leo Varadkar is to make a statement to the Dáil on Tuesday about the matter.
Mr Martin said the Tánaiste will "answer comprehensively" any issues, adding that he has confidence in Mr Varadkar.
"I don't have an issue with us working together," he added.
Mr Martin refused to say whether he thinks Mr Varadkar should apologise to the Dáil.
He also said that if the document was published sooner, it would have "averted" the incident.
Mr Martin said he is not aware of any other correspondence between Mr Varadkar and the former chair of the NAGP.
Micheal Martin added: "I don't believe any law was broken in relation to this.
"I think in terms of future practice, lessons can be learned from this and in life we all can learn from previous experience.
"The objective of the last Government was to get (the deal) over the line as it would advance primary care.
"It was an agreement that should have been published sooner. But it's noted that the NAGP were being consulted and there were commitments made about the progress of those negotiations and talks.
"It's the manner in which this happened that is inappropriate."