Health services in Northern Ireland risk "deteriorating to the point of collapse" without a long-term funding strategy to support transformation, a report by a Westminster committee has said.
It said services are struggling to meet the needs of an ageing population.
The report added that the services are "lacking adequate financial support or strategic guidance".
The Department of Health said it would carefully consider the recommendations.
The warning comes as the department spelled out the scale of the budgetary pressures it faces in a letter to Northern Ireland's political parties.
The Westminister committee report, by the Northern Ireland Affairs Committee, said key services, "in particular cancer, social care and mental health", lack comprehensive strategies to guide their future direction.
It added that the Department of Health "must do more to demonstrate its commitment to developing long-term strategies for these services".
The committee said the department must also take immediate action to tackle "acute issues facing the health service".
These, it said, include cancer waiting times, shortages in social care staffing and inadequate mental health funding.
The report said decisions over health services in Northern Ireland are the responsibility of the health minister in the Northern Ireland Executive, but that if the Northern Ireland Assembly was not formed by the end of the year, the government will need to take action.
A government spokesperson said health and social care services in Northern Ireland were "a devolved matter".
The spokesperson added that Northern Ireland Secretary Julian Smith had visited a number of health and social care facilities and "fully understands the pressures that the sectors are facing".
"That is why he is doing everything he can to get the Stormont institutions back up and running as soon as possible, in order that local politicians make decisions affecting everyone in Northern Ireland.
"The secretary of state will consider the recommendations contained in the report and respond in due course."
The letter, meanwhile, which the Department of Health sent to MLAs who lead on health in Northern Ireland's political parties, spells out the specific pressures under which it is operating.
The issues include:
- Waiting Lists - the department estimates that about £100m a year would be required to tackle hospital backlogs;
- Pay parity - the department says that offering Northern Ireland staff parity with wages in Great Britain would add £103m to the bill;
- Employers' contributions to staff pensions - this is a UK-wide issue and could cost £144m;
- Ambulance service - an investment of up to £30m is needed for its new clinical response model;
- Medical training - up to £30m is needed to support graduate entry medical training places;
- Specialist drugs and therapies - including specific cancer therapies - could cost up to £26.8m;
- Nursing places - maintaining these could cost up to £42m in future years.
Northern Ireland Affairs Committee chair Simon Hoare said the health service in Northern Ireland was falling behind the rest of the UK.
"An approach to funding that simply keeps things ticking over, and an absence of over-arching strategy in key areas, has left services at breaking point and this situation must end as soon as possible," he said.
"We have called for the government to end the insecurity and set three year minimum budget allocations to give vital services the space to breathe and look ahead.
"We also expect more regular updates on the progress in developing strategies in key areas, particularly cancer services and mental health."
One of the key findings of the committee was that the "transformation of Northern Ireland's health and social care services is long overdue".
It said the UK government should also work with the Department of Health and Department of Finance to produce three-year minimum budget allocations.