Shadow health secretary Andrew Lansley has accused the Department of Health of inconsistency after it argued both for and against compelling drug companies to provide more information about clinical trials in a single day.

On Wednesday last week, health minister Dawn Primarolo announced that she would strengthen the law to make companies provide information relating to public safety. The move came after the government decided not to prosecute GlaxoSmithKline for withholding clinical trial information about the safety of its drug Seroxat from the Medicines and Healthcare products Regulatory Agency.

There was no real chance of a prosecution succeeding because of the legislation in place at the time, she said.

But on the same day, the DH issued a response to the Commons health select committee report on the National Institute for Health and Clinical Excellence, in which it argued against new powers to compel pharmaceutical companies to provide it with more information about clinical trials.

The response said: "NICE is currently able to treat information in commercial confidence if requested to do so by the manufacturer, and has not asked the Department of Health for powers to compel companies to provide more information. We do not believe that a persuasive case for taking such powers has yet been made."

Mr Lansley acknowledged that two different sorts of information were needed by NICE and the MHRA, but said: "The government is saying it needs new legal powers to get information that should be available voluntarily.

"Now would be the time to consider whether such powers need to be available more generally, otherwise we could be in a situation where a drug is licensed but its clinical effectiveness and cost effectiveness is not transparent to the NHS."

A DH spokesperson said: "These are two different issues. NICE is looking at clinical effectiveness and cost while the MHRA looks at safety. NICE has not asked us for any changes to be made."

NICE declined to comment on the report ahead of a discussion at its board meeting next week.