Southern District Health Board member Malcolm Macpherson said it was unclear whether boards had the power to reject the proposal, which could see mega-kitchens in Christchurch and Auckland producing meals for the country.
The process is being run by Health Benefits Ltd, a Crown-owned entity which is cutting costs in the health sector.
''It's unclear to me ... how much independence individual DHBs will have when it comes to the crunch with these things.''
Dr Macpherson believed the closer the decision was to next year's general election, the less likely it was the Government would want a controversial outcome.
As a retiring member, Dr Macpherson would not have a say, but he believed there would be resistance, as the Dunedin Hospital kitchen was a source of pride.
''We think we do [meals] really well. Our patients tell us we do it really well, unprompted.''
There could be significant pressure for DHBs to all fall in line, he said. It was likely a DHB would determine the limits only by testing them.
There was a danger the centralisation proposal would exacerbate parochial tensions.
''In the South Island context, we often get kicked round a bit by Canterbury.''
Health Benefits Ltd spokesman Mark Reynolds said the business case would be considered by DHBs, and the sector as a whole would decide how to proceed.
''What we want to do is put together a compelling proposition that makes sense. When we've done that then we can have some further discussion.''
Asked if DHBs could reject the proposal by voting it down, he said he could not ''talk for DHBs'', but he had not heard the process would involve board members voting.
Mr Reynolds said the business case was likely to go before boards early next year, and he defended the time the proposal was taking..
''We're talking about a national programme looking at all of the options for food delivery for people at 20 DHBs, from Cape Reinga to the Bluff.''
Much incorrect information had been published about the proposal, and he maintained that the location of the centralised kitchens had not been decided.
Implementation was likely to be later next year. Southern DHB chairman Joe Butterfield refused to comment when contacted, saying it was ''all being handled by HBL''.
