There is no guarantee that NHS workers in Northern Ireland will benefit from the proposed pay offer worth between 6.5% and 29% over three years, it has been warned.
The proposed deal, agreed at a meeting between 14 unions and NHS employers, signals the end of the Government's controversial public sector pay cap.
Under the agreement, the pay of the lowest-paid staff, such as porters and cleaners, will increase by 15%. Half of NHS workers are at the top of their pay band so will receive a 6.5% increase. The other half will get between 9% and 29%, with midwives and physiotherapists among those in line for the biggest increase.
If the agreement is accepted, the extra funding for English health budgets will go through the Barnett formula into budgets in Wales, Scotland and Northern Ireland. This will allow unions, devolved governments and employers to hold discussions on whether and how they want to implement the framework agreement for their health staff.
However, the Ulster Unionists warned that with no Executive in place, the funding could be instead be used to plug "the black hole in Northern Ireland's finances".
Health spokesman Roy Beggs MLA said: "The UUP has long argued that because health workers here are signed up to the NHS's wider UK terms and conditions, they should be treated no worse or paid any less than their counterparts in England, Scotland and Wales, yet that is exactly what has been happening for some time. Now, with this latest increase of over 6%, the gap is going to widen even further.
"Whilst the pay increase in England will see more money coming to Northern Ireland through the Barnett funding system, there are absolutely no guarantees or even suggestions as of yet that the money will be used to pay for a similar pay increase here.
"A local minister and Executive could ensure the money was spent on a pay deal, so I fear instead it will simply be diverted to the black hole in Northern Ireland's finances."
Janice Smyth, director of the Royal College of Nursing (RCN)in Northern Ireland, said that the deal was currently for staff working within the NHS in England only.
"However, the RCN is committed to UK-wide pay, terms and conditions. We are assured that Northern Ireland will receive NHS funding for pay and we therefore expect the same deal to be implemented for nurses in Northern Ireland," she explained.
"It is essential that nurses in Northern Ireland not only receive the same pay deal and entitlements as their colleagues elsewhere in the UK, but also that the deal negotiated here redresses the pay inequality to which nurses in Northern Ireland have been subject for far too long.
"This is what the RCN in Northern Ireland will be working to secure in the coming weeks."
Kevin McAdam, of the Unite union, welcomed the deal, but called for it to benefit all Northern Ireland healthcare workers.
"It is vital that this pay improvement be passed on fully to healthcare workers in Northern Ireland to ensure that our rates of pay do not fall further behind those in the rest of the UK," he said.
"The fact that workers here are currently paid less than their equivalents in England, Scotland and Wales is inducing workers to take up positions outside the region and is resulting in severe pressures on local healthcare services and provision.
"The announcement represents an opportunity for the health and social care trusts to address the challenge of pay inequality for Northern Ireland's healthcare workforce. We need to see pay parity on the back of this announcement."