The ICU was recently granted C12-level accreditation by the College of Intensive Care Medicine, a certification revoked in 2014.
The ICU is also set to double its capacity with the opening of 11 more beds in the coming months.
Service manager Shayne Wylie said the accreditation was an outstanding accomplishment and the result of many people’s efforts.
"Over the last few years, our team has wholeheartedly embraced the mission of getting training accreditation," he said.
Despite an appeal, the training accreditation was withdrawn in 2014 primarily due to the state of the unit, reportedly described as "dated" by assessors.
"Since 2014, our ICU has undergone a significant upgrade to not only fulfil accreditation requirements but also to bring our facility up to modern standards to meet the needs of our patients," Mr Wylie said.
Improvements had been made in a number of areas, including an upgrade to facilities and improved staffing levels, case loads and research and teaching programmes.
"The exceptional echocardiography training, simulation programmes and supervision received high praise and was described as ‘excellent’ by [the college]," he said.
The C-12 accreditation permitted the ICU to provide up to 12 months of general training and subspecialty accreditation in cardiothoracic intensive care and trauma intensive care.
Stage one of a new ICU opened in 2018, while stage two - earlier expected to open in mid 2019 - was due to be completed in three or four months.
This was because of work needed to upgrade the heating, ventilation, and air conditioning systems.
Work was progressing well, he said.
The ICU operated with 11 beds, but the opening of stage two would bring this to 22.
"We are now working to recruit and resource staff to maximise the use of these additional beds."
The accreditation gave more options for trainees to train in the South Island, and the ICU team was "thrilled" at the achievement
The team was now working towards being accredited for 24 months.
