National wants the Auditor-General, Parliament's independent spending watchdog, to run a ruler over the $1.9 billion for mental health allocated in the 2019 budget.
The Auditor-General normally looks into whether laws might have been broken around the spending of public money, not the merits of individual spending decisions.
It would be unusual for there to be an examination of an entire Government spending package without there being evidence of the spending itself being inappropriate.
However, National's mental health spokesman Matt Doocey said that the Auditor-General had recently raised concerns about the lack of oversight of the Government's mental health package anyway. He has written a letter to the Auditor-General to ask for a full investigation into those concerns.
Health Minister Andrew Little said the spending had already been reviewed six times across a range of reviews.
"The way the fund is being spent has been looked at by the Department of Prime Minister and Cabinet's Implementation Unit, in two reports from the Mental Health and Wellbeing Commission and three times by the Auditor-General's office as part of its regular audits of the Ministry of Health and district health boards," Little said.
He described the call for yet another review as a "meaningless stunt from a party that left our mental health services in an appalling state, handing us with task of a major rebuild".
Doocey justified his call for a further review of the spending with a finding from the Auditor-General contained in a previous report.
He said the Auditor-General's report on "Observations from our central government audits" raised concerns that there "were no performance measures assessing the extent of the public's greater access to mental health services".
It also said that "Budget initiatives to expand mental health services did not result in any changes to the performance information".
Doocey told the Auditor-General that he had tried three times to get the Health Select Committee to look into various mental health issues, including the concerns raised about spending. He was voted down each time by Labour, despite Doocey having the support of other parties. It was only after doing this that he turned to the Auditor-General.
"In the last three weeks Labour has used its majority on the Health Select Committee to block my call for briefings on the lack of outcomes from the $1.9b announced by Labour for mental health, from the Mental Health and Wellbeing Commission, the Ministry of Health, and the Auditor-General," Doocey told the Herald.
"All three requests for briefings have been supported by Act, the Greens and the Māori Party, but Labour members on the committee have used their majority to vote them down," he said.
The Government allocated $1.9b in funding for mental health in the 2019 Budget. Even Little has voiced concern at the way some of the spending had not filtered through to improvements in the sector.
Little said "Doocey is cherry-picking bits from the latest report of the Mental Health and Wellbeing Commission to suit himself".
"The $1.9 billion in the 2019 Budget package was for primary and community mental health services, areas ignored by the previous Government and identified in the He Ara Oranga report as being where the greatest need is," he said.
"In fact, the Mental Health Commission says the Government has made a promising start on addressing the recommendations from He Ara Oranga and commended our investment in "much-needed primary and community services".