The announcement of the veto was made after a cabinet meeting today to discuss what action the government should take after an Information Tribunal ordered it to publish the transitional risk register into the implementation of the Health and Social Care Act.
A DH spokesman said Mr Lansley consulted the cabinet before using the ministerial veto which the Freedom of Information Act allows.
The ministerial veto has been used on three previous occasions. Once when disclosure of cabinet minutes on Iraq was ordered and on two separate occasions relating to the order of disclosure of minutes of the cabinet sub-committee on devolution.
In a bid to appear open and transparent, the DH today published a document which sets out key information relating to the areas of risks in the original risk register. It also sets out the mitigating actions that have taken place since November 2010 and which are planned in the future.
Today, the DH also published a Scheme for Publication, which will set out proposals for reviewing and releasing material relating to the transition programme in the future.
This comes after an information tribunal published its judgment on 5 April, explaining why it ordered the DH to publish the register listing fears about the impact of the reforms. It said the way the reforms were introduced was 'exceptional' because a White Paper was published without consultations after the Conservative manifesto promised no 'top-down' NHS reorganisation.
The DH lost its appeal to the Information Commissioner’s Office ruling last November which ordered it to publish the transitional risk register after a Freedom of Information request in 2010 by the then shadow health secretary John Healey.
An ICO spokesman said: 'We will need to study the secretary of state’s statement of reasons for imposing the ministerial veto in this case. These must, under the criteria established by the government, be 'exceptional'.
'We will present the commissioner's formal report on the matter to parliament next week.'
Today, Mr Lansley said: ‘This is not a step I have taken lightly. I am a firm believer in greater transparency and this government and this department have done far more than our predecessors in publishing information about the performance and results of our policies. But there also needs to be safe space where officials are able to give ministers full and frank advice in developing policies and programmes. The Freedom of Information Act always contemplated such a ‘safe space’ and I believe effective government requires it. That is why cabinet has today decided to veto the release of the department's transition risk register.
‘Had we not taken this decision, it is highly likely that future sensitive risk registers would turn into anodyne documents, and be worded quite differently with civil servants worrying about how they sound to the public rather than giving minister frank policy advice.
‘To continue to be transparent about the risks we considered, and to be equally clear about how we have mitigated those risks, I have also published today a document setting out key information relating to the areas of risks in the original risk register, how we have met those risks head on and how we will continue to do so. The public continue to have all the information necessary to understand what we considered the risks to be and how we have acted to mitigate them.’
Editor's blog: Why the DH shouldn't publish the NHS reforms risk register