Health sector unions have advised their members not to cooperate with HSE management's attempt to force all staff to work the increased hours negotiated under the Haddington Road Agreement.
In a letter to managers yesterday, HSE Director of Human Resources Barry O'Brien urged them to squeeze every possible saving from the HRA before considering cutting services.
Under the agreement, staff who did not want to work the increased hours were permitted to retain their existing hours with a pro rata pay cut.
However, Mr O'Brien's letter states that what he calls the "concession" allowing staff to retain their existing hours is no longer viable.
He said that from 1 January, all staff must work the increased hours set out in the HRA.
Chair of the staff panel of the health sector unions Phil Ní Sheaghdha has written to the chair of the HRA oversight group Kevin Foley asking that the oversight group be convened immediately to deal with the issue.
She described the situation as a direct breach of the agreement.
In her letter, she tells Mr Foley that the health sector unions will advise their collective membership that they are not required to co-operate with the instruction from the HSE.
Mr O'Brien's letter to managers also confirms that there will be a targeted voluntary redundancy scheme available from 1 January.
Hoever, the document does not specify the number or redundancies sought.
SIPTU has sought an urgent meeting with the HSE to discuss the redundancy scheme.
Speaking on RTÉ’s Morning Ireland, SIPTU Health Division Organiser Paul Bell said there is an urgent need to clarify what the HSE means by "targeted" redundancies.
He said the union will not accept if health services its members provide are compromised as a result of this action.
"The question is what is targeted, and because of the nature of the communication, employees of the HSE and voluntary hospitals had no understanding that such a communication was going to be issued.
"I suppose if we had discussions with the HSE and Department of Health up to this point we would have understood what they meant.
"But what we're not prepared to accept is that health services that we offer are going to be in any way compromised," Mr Bell said.