MidCentral District Health Board is blaming ongoing work force challenges and increasing demand for another blowout in its ultrasound waiting list.
In December there were 293 people waiting longer than the five-month target - almost 100 more people than in September last year.
Managing the wait has regularly been a problem for the health board, with Medical Imaging team leader Diane Orange calling the problems "longstanding and challenging".
"Scarcity of sonographers is recognised not only locally but also regionally, nationally and internationally," she said.
"Waiting times have increased due to a decrease in sonographer availability, as a result of vacant positions."
MidCentral is currently staffed to fill 0.7 of a fulltime sonography position and has three fulltime trainees.
Ms Orange said that in addition to the work force challenges, the demand for ultrasound services continued to increase.
In June last year the Manawatu Standard reported that some ultrasound patients had a nine-month wait ahead of them for scans.
At that time the board was working to reduce the list, which peaked at 356 in January, 2013.
Ms Orange said the service remained committed to providing timely access to ultrasound, within established guidelines, and to ensure that "over time" it had no patients waiting longer than five months for an examination.
"All urgent examinations are still being seen within established time frames," she said.
"All ward patients are being seen the day of their referral. Careful attention is given to the prioritisation of referrals to maintain patient safety."
Ms Orange said initiatives to reduce ultrasound waiting times included weekend sessions at Palmerston North and Dannevirke, and some Palmerston North patients were being seen on Mondays at Dannevirke.
"The DHB is also filling current vacancies - a fulltime permanent sonographer will be employed from July and a second sonographer has been interviewed with the potential to start also July this year," she said.
"Locum sonographers from within New Zealand are assisting as available during the week and radiologists are assisting with more hands-on scanning with more specialist procedures."
There was also a list of patients who were available at short notice to fill slots caused by late cancellations of appointments.
Ms Orange said that as a result of these measures, almost 100 more people were scanned in January compared to December.
However, she said the waiting list continued to grow due to the ongoing demand on the service.
- Manawatu Standard
Will the bus shelter walkway planned for The Square be ready by the end of June?Related story: Covered walkway for Palmerston North bus users by winter