Speaking at yesterday's committee meeting in Invercargill, Mr Thomson said the 2011-12 deficit reduced recently, partly because of changes to how some income and liabilities were recorded.
The DHB recently reworked the calculation of some of its liabilities to comply with accounting best practice. The change helped bring down the deficit, from $15 million-$15.5 million to an unaudited $12.7 million.
However, this meant issues might be deferred, Mr Thomson said.
Whether or not it was the right thing to do was a different question from whether the public deserved to know, and he thought they did.
"My concern is that the public is entitled to know."
Mr Thomson said moving liabilities to future years was "exactly" the kind of situation that caused a financial problem in another year.
The DHB must not "bury" the matter in the closed-door audit and risk management committee, or the public-excluded section of the full board meeting.
"That to me [the public's right to know] is a matter of importance."
Moving liabilities from one year to another was "entirely germane" to the wider financial picture, and should be disclosed publicly, Mr Thomson said.
Committee chairman Paul Menzies and others expressed concern the financial matters were so complicated, they risked confusing the public.
Board chairman Joe Butterfield said Mr Thomson was putting the "cart before the horse" because the issue had not been reported through to the audit and risk management committee today, which would then be discussed behind closed doors at the full board meeting today.
As yet, there were so many unanswered questions about how and when the financial costs would fall it was too soon to quantify their impact, Mr Butterfield said.
"The whole thing is still in the pot," he said.
