A Government appeal will be heard on Monday against a ruling which says it must publish a risk assessment of its controversial NHS reforms.
In November, the Information Commissioner concluded there was a "very strong public interest" in disclosing the risk register, which details the potential impact of the Health and Social Care Bill.
The Department of Health had earlier refused a freedom of information request to publish the register, saying there is a stronger public interest in withholding the register from public scrutiny than in publishing it.
The department told the commissioner it must be able to use the register without fear the information will be put in the public domain "in an unmanaged way" while its policy continues to be developed.
The commissioner rejected those arguments and ordered the register be published.
On Monday, the Information Rights Tribunal will hear the Government's appeal against the commissioner's decision.
Health Secretary Andrew Lansley has said it would be "completely misleading" to publish the register, which was put together before changes were made to the Bill and had been intended as an "internal mechanism".
He said that, to be effective, a risk register requires all those involved to be frank and open about potential risk.
Labour argues that full disclosure is needed and local risk registers already show the scale of damage that could be done to the NHS by the Bill.
Shadow health secretary Andy Burnham has said some of the regional risk registers "predict poorer treatment for cancer patients".
In one example, South Central Strategic Health Authority warned "the pace and scale of reform, coupled with savings achieved through cost reduction rather than real service redesign could adversely impact on safety and quality", he said.
NHS London's report identified "a risk that women could be exposed to unsafe services which could cause them harm".
The British Medical Association (BMA), the Royal College of GPs and the Royal College of Nursing (RCN), which all want the Bill scrapped, have also called for the register to be published.
Last month, MPs voted by 299 to 246, a Government majority of 53, against Labour's motion calling on ministers to release the register.
If the latest hearing, which is set to last two days, goes against the Government, it still has the right to appeal to an upper tribunal run by the tribunal and courts service.
A Department of Health spokesman said: "Risk registers are departmental management tools that play a key role in the formation of Government policy. We believe that their publication would risk seriously damaging the quality of advice given to ministers and of any subsequent decision making."
He said a substantial number of risks relating to the Bill had already been set out in a separate impact assessment.
Mr Burnham said today the Government must "come clean", adding: "It's essential that patients, the public and Parliament knows the full scale of the risk the Government is running with the National Health Service before approval is given to this Bill."
He added: "The public needs to know what are the full scale of the risks that the NHS is facing before this debate is concluded.
"These issues that will be in the risk register go to the heart of NHS services, whether they are safe, whether they are good quality and whether we can continue to rely on the health service .
"We've already got data from local risk registers in the NHS and they reveal some very worrying things."
Prime Minister David Cameron said last month that Mr Burnham had blocked the publication of a risk register in September 2009, when he was health secretary.
Mr Cameron said it showed Labour "absolutely revealed as a bunch of rank opportunists, not fit to run opposition and not fit for government".
Mr Burnham said that register related a whole range of things the Department of Health was looking at, including pandemics and terrorism.
"My argument is I wasn't initiating the biggest ever reorganisation at a time of financial stress," he said, adding there was no Information Commissioner ruling in his case.
Unite's general secretary, Len McCluskey, said: "Andrew Lansley is deceiving the public about the true implications of the Health and Social Care Bill by his dogged refusal to publish the risk register."
He said the refusal was "recognition that the reforms will risk patient care and cost millions to implement - taxpayers' money which should be spent on patient care. "What have they got to hide?"