The P.E.I. government underspent on its addictions and mental health treatment budget last year because it had trouble filling positions, says Health Minister Doug Currie.

Currie was taken to task by the opposition Wednesday for leaving $1 million unspent in the budget.

Currie said it can be hard to keep positions in addictions filled.

"Some areas of addictions it's a little more challenging to attract, particularly nurses, to positions," he said.

"That does at times have an impact, there's no question, I mean you need to staff, you need to resource these facilities appropriately."

Last May Health PEI shut down detox beds at the the Mount Herbert treatment centre. There were four vacancies in the unit, including two registered nurse positions.

Currie said steps have been taken to address an overall shortage of nurses, including the introduction of the accelerated nursing program at UPEI.

The budget for addictions services has increased for 2014-15, up to $11.6 million compared to $10.1 million spent last year.