The number of patients waiting more than a year to see a consultant has risen.
Nearly 95,000 outpatients were left waiting more than 52 weeks for a first consultant-led appointment at the end of December 2018, new figures from the Department of Health show.
This is up from 80,651 in December 2017.
Overall, more than 281,705 people are waiting for a first appointment with a consultant, up from 271,553 the previous December.
By March 2019, 50% of patients should wait no longer than 9 weeks for a first outpatient appointment, and no patient should wait longer than 52 weeks.
Waiting times for inpatient treatment have also risen with 21,477 patients waiting more than a year for inpatient treatment.
The Department of Health said that while transformation is underway, sustained investment was needed to “clear the backlog of patients waiting for treatment”.
Roy Beggs, Ulster Unionist health spokesperson, said the £30m funding package, made available through the DUP/Conservative confidence and supply arrangement, had “simply not worked”.
The MLA added: “Our health service is in the midst of a wholly unprecedented crisis – both in terms of scale and severity.
“A figure of 95,000 outpatients alone waiting longer than a year to see a consultant, out of a population of only 1.8million, is as staggering as it is terrifying.
“If these equivalent hospital waiting times were occurring anywhere else in the UK it would rightly cause outrage and be a national scandal, and yet in Northern Ireland it is now simply taken for granted that every publication of figures will be worse than the one that came before.
“Health waiting times are reported as a trigger for actions as it is medically accepted that the longer patients are forced to wait for treatment, the greater the harm they may ultimately come to. There is no doubt whatsoever that the health of local patients is being adversely affected by the delays.”
He called on the Secretary of State needs to intervene and said crucial health decisions were being deferred as a result of the political stalemate at Stormont.
SDLP health spokesperson Mark H Durkan said waiting time targets “despite not being overly ambitious in the first instance” have once again been missed.
“The detailed statistics related to all medical appointments, whether they be a consultant-led outpatient appointment, a diagnostic test or inpatient and day case admission, show that the majority of patients here have had to wait much longer than targets suggested they would,” he said.
“What has to happen for the DUP and Sinn Féin to recognise the real life impact on our constituents before they act to make this place work for everyone? Their inability to make it work for the health and well-being of our people here tells a story in itself.”
In a statement, the Department of Health said: “As has been set out clearly in the past, not least in our Transformation Plan, our service is simply unable to keep pace with growing demands for treatment, despite the best efforts of staff.
“Funding of £30 million has been provided this year which by the end of December had resulted in an additional 79,000 assessments or treatments.
“However, this investment has only managed to slow the overall growth in waiting times – a fact which underlines the scale of the challenge facing the system.
“Fundamental transformation remains the only long-term answer to this problem. While transformation is underway, sustained investment is also required to clear the backlog of patients waiting for treatment.”