Internal emails from the chairman of NHS Lothian reveal plans to drip-feed Audit Scotland details of private board meetings.
It had gone to the board – which was involved in a scandal over manipulated waiting times in 2011 – with a routine request for papers.
But in a message to board members and senior executives yesterday, Dr Charles Winstanley said: "Audit Scotland are, of course, technically entitled to any information, but we would offer no more than minutes."
He emphasised the "brevity" of the notes which NHS Lothian is willing to share with the auditors.
The message – timed at 12.20pm yesterday – followed Audit Scotland's indication it would like to see future non-specific material relating to the private board meetings.
An NHS Lothian spokesman confirmed "waiting times issues would have been discussed at private board meetings" after the scandal was exposed in late 2011.
But Dr Winstanley insisted Audit Scotland had only asked for details of future meetings. He offered to provide minutes of those and the most recently held meeting. Scotland's health boards are obliged to provide full information of all private meetings to Audit Scotland.
An internal inquiry last year found NHS Lothian had manipulated waiting times by offering patients treatment at short notice in England then marking them as unavailable if they could not attend.
An independent inquiry into the scandal last year, ordered by then Health Secretary Nicola Sturgeon, found a culture of bullying among Lothian health service bosses.
An initial email seeking colleagues' views on Audit Scotland's request was sent by Dr Winstanley at 3.33pm on Monday.
It noted: "We have no control over the conclusions that Audit Scotland might draw from papers they received."
Yesterday's follow-up added: "Audit Scotland are, of course, technically entitled to any information, but we would offer no more than minutes at this stage."
It is understood the proposal was made by Susan Goldsmith, NHS Lothian finance director.
More than 20 people were copied in to the first email and more than 30 to the second – though they did not include Tim Davison, the NHS Lothian chief executive.
An Audit Scotland source said the watchdog expects to receive details of all private meetings of Scotland's health boards, which are usually held to discuss commercial contracts, disciplinary cases and other sensitive issues.
Labour's health spokeswoman Jackie Baillie said: "NHS Lothian's conduct in all of this has been shocking. To now find out the board is seeking to drag its heels and attempt to hold back information from Audit Scotland is simply unacceptable. The health board needs to get a grip and stop the secrecy. The Scottish Government must now intervene and send in a taskforce to both clear up the historic mess and turn around the present performance failings."
NHS Lothian apologised after a Government-ordered internal inquiry confirmed waiting times had been fiddled.
Figures highlighted last month suggested waiting times have been manipulated across Scotland.
A total of 17,360 patients were deemed unavailable for treatment for social reasons in December 2011, when the NHS Lothian scandal broke. But the figure had almost halved by September 2012. Large falls were recorded in all mainland health board areas.
Dr Winstanley said: "We work with Audit Scotland on a regular basis and they already know that they can have full unedited access to whatever they are seeking.
"It was anticipated that minutes of our private board meetings would be sufficient in the first instance for Audit Scotland, but of course they can have whatever other documents connected to the meetings they may wish to see.
"The emails I sent out were as a courtesy to all board members to gauge their opinions on this request, as it concerns private meetings at which they were present. To suggest that this constitutes any sort of obstruction of information is mischief making and I am disappointed that anybody would interpret the emails in that way."
An Audit Scotland spokesman said: "We recently made a routine, standard request for information to which we are entitled and which may be of interest to us in our audit work."