Hospital waiting times have increased because of the cost of tackling swine flu, according to the Health Minister.
Latest figures showed the number of patients waiting over nine weeks for a first outpatient appointment increased from 1,114 in June 2009 to 4,559 in September.
The figures also showed that, at the end of September, there were 2,975 patients waiting longer than 13 weeks for surgery, compared to 1,117 in the previous quarter.
Michael McGimpsey said he was disappointed and called for health and social care staff to focus their efforts on addressing the problem.
But he insisted that progress had been made since 2005.
"Hospital waiting times today are unrecognisable from the long waits endured by patients only a few years ago," he said.
"The vast majority of patients continue to receive their care and treatment within a reasonable period."
The Minister explained that waiting list work had been suspended by trusts during the summer until uncertainty over the swine flu budget was clarified.
He said: "Following the confirmation by the Executive of funds of £32m to meet half the £64m cost in late September, waiting list work has restarted.
Mr McGimpsey said the Health Service is currently under severe strain trying to respond to significant increases in demand for services within the limited funding available.
"In the last year alone, there has been an increase of 8% in demand just for elective care services, yet our funding has only increased by 0.5% in real terms, the lowest rise in living memory," he said.
The Minister said the increase in demand in the first six months of 2009-10 was equal to an additional 35,000 first outpatient appointments and 9,000 more inpatient and daycase procedures.
"The number of hospital staff has not, however, increased and instead staff have been stretching themselves to the limit to meet this growing demand."
© UTV News