The Fianna Fáil leader, Micháel Martin, has accused the Taoiseach, Leo Varadkar, of a cynical attack on doctors and nurses.
It comes after Mr Varadkar suggested they should not be allowed to take time off over the busy Christmas period.
Earlier this week in the Dáil Mr Varadkar called on hospital consultants, nurses and other medics to forego extended leave over Christmas and New Year to manage peak demand.
Opposition parties have called for him to apologise following the comments.
Mr Martin thinks the Taoiseach is trying to blame someone else for the Government's failures in the health service.
He said: "It was an outrageously cynical ploy by the Taoiseach to attack nurses and consultants around the Christmas break.
"He was deflecting and also trying to blame somebody else for his own failings and the failings of his government in not having a plan."
A clinical director at Cork University Hospital has said the Taoiseach's comments are “bordering on being disingenuous and insulting.”
Dr Mike O’Connor, who is a consultant geriatrician, said he did not know of any senior consultants who are rostered off in early January. He is on call himself on December 25 and December 26.
He told RTE’s Morning Ireland that he could “absolutely and categorically say” that fewer consultants will be on leave in January than at any other time of the year.
Dr O’Connor said that hospitals “work full whack” during the holiday break, he said.
Some have been rostered to work over Christmas and others have volunteered, he added.
Dr O’Connor said that at Cork University Hospital they see 70,000 emergency department admissions per year, “that’s nine people every hour of the year.” There are always pressures on the service “winter has nothing to do with it.”
He acknowledged that it will be “a little more tense” with the number of weekends and bank holidays coming together, but that as part of the hospital’s winter plan there will be “serious decision makers” on duty including anaesthetists and specialist surgeons.
“That doesn’t change, they will be on call or on site.”
He said it was bordering on being disingenuous and insulting “to suggest that significant tranches of the HSE roster themselves to be off” at Christmas.
When pressed, he said he thought less than 10% would be on leave in early January.
Dr O’Connor said that Irish hospitals deal with 1.3 million attendances per year, a growth of 5% per year. That figure includes 40,000 patients who spend more than 24 hours on a trolley.
“There is not a cogent, collective, collaborative plan to address this problem that has been going on for 15 years.
“It is bogus to categorise this as a November to January problem.”