New operating theatres, wards and an expanded emergency department will open at Christchurch Hospital in 2018.

Canterbury District Health Board has been hailed the best financial operator in the country and amongst the best at keeping patients out of hospital by caring for them in the community.

So it is deeply troubling that its business case for 400 beds in the new acute services building has been rejected due to budget constraints.

Health board members heard on February 18 that two wards, each to hold 34 beds, would not be fitted out in the new building due to open in 2018.

The acute services building will cost about $445m and will house 12 operating theatres, an expanded emergency department and intensive care unit, as well as wards over six floors. Space was to have been created for 140 beds on top of the 400 initially planned, to allow for future expansion.

The decision to defer the fit-out of two wards was made jointly by the Hospitals Redevelopment Partnership Group (HRPG), the Treasury and the Ministry of Health. Canterbury District Health Board chairman Murray Cleverley, who sits on the partnership group, said it was hoped cost savings across the rebuild project would help fund the fit-out before the building opened.

However, no details have been revealed about the size of this funding black hole.

Behind the scenes it is understood some health board members are deeply skeptical that sufficient savings can be made during construction, pointing out few building projects have come in under budget in post-quake Christchurch.

So if the new beds do not open, what will that mean for services?

Canterbury's population, like much of New Zealand, is ageing; the 2013 Census found the proportion of Cantabrians aged over 85 had leapt 23 per cent in seven years. With an ageing population comes an increase in demand for health services.

Chief executive David Meates has described the district's health system already as "starting to implode".

Yet in 2014, the CDHB was ranked the top-performing health board in the country by the auditor-general. And it has had international recognition for its ability to integrate hospital-level and community care.

Despite this it appears to be in frequent dispute with the health ministry over funding.

It has battled for ministry support to meet rising demand for mental health services, particularly among the children and youth of this earthquake-hit city. Figures obtained by The Press indicate Canterbury's mental health funding will drop to about $210 per head of population, while the national average increases to more than $250.

Canterbury has also requested more funding for its emergency department, describing it as under "real, sustained pressure". And it has shown it was $8m underfunded for the number of overseas patients it was treating.

So why is the health minister not fronting his ministry's funding decisions here in Canterbury?

Jonathan Coleman has not met with the district health board once since taking office, despite Canterbury being one of the largest health boards in the country with a population of 530,000 people stretching from Kaikoura to Ashburton.

This is not good enough. We challenge the minister to meet our health board, in public and face-to-face, to explain why he does not believe it needs more money for mental health, for its emergency department, or for those 64 new beds.