However, HBL spokesman Steve Fisher said no hospital or clinic kitchens would close as a result of the proposal. Staff would have the opportunity to transfer their employment to Compass Group, which would consult staff if future changes were required.
Northland DHB general manager of finance, funding and commercial services Meng Cheong said, "Northland DHB management have some concerns which we are seeking to discuss in more detail with HBL/Compass."
A meeting between the two parties was scheduled for July.
"This due diligence process will help inform the board on the pros and cons, risks and rewards of either approving or rejecting the national food business case," he said.
The proposal seeks to streamline food production creating two hubs - in Auckland and Christchurch - with meals transported to the regions and reheated.
The plan was drawn up by HBL, a Government-owned organisation set up to find savings in the sector.
The contract for the national food service was awarded to international catering giant Compass Group.
Mr Fisher said the proposal to Northland DHB included two ways food would make it on patients' plates.
Some snap-frozen meals made in Auckland would be delivered by truck and reheated and plated at Northland hospitals.
In other cases meal ingredients, fresh and frozen, would be sourced from the Auckland hub and prepared and cooked in Northland hospitals.
"A range of different food delivery, preparation and cooking methods are being considered by all parties," Mr Fisher said.
The proposal would also be subject to consultation with staff and unions.
