The government has said it is highly unlikely that a tribunal judgment on releasing a confidential risk assessment of its health reforms would be delivered before the legislation’s next stage through parliament.

Labour has previously called on the government to publish the risk assessment. The government meanwhile is appealing against a decision by the information commissioner Christopher Graham, who ruled recently that ministers were wrong to keep the risk register under wraps.

Liberal Democrat Baroness Williams of Crosby, a former Labour cabinet minister and a leading critic of the Health Bill, called for moves to hasten a decision on the matter, stating it was “quite clear” that the decision was “very germane” to the report stage and highly relevant.

She said: “There is a real difficulty if the appeal has not been heard, if it hangs over the report stage and as a result leaves people able to say, but if the appeal had gone the other way then X and Y would follow.”

Baroness Williams said it was crucial to ascertain whether “steps are being taken to accelerate the process as much as possible” to enable the report stage to start properly at the end of January.

Cross-bencher Lord Owen said the question of risk assessment was “absolutely central” to the judgments that had to be made at the report stage of the Health Bill and said he hoped peers did not proceed to that stage until the tribunal’s judgment had been heard.

Referring to the timetable of the appeal, health minister Earl Howe said he recognised fully the strength of feeling on the issue and “the desire for speedy resolution”.

He said the timetable was a matter for the Information Commissioner and indicated he would write to Baroness Williams to give as much information as possible on the likely timetable for the process.

Liberal Democrat Lord Willis of Knaresborough said it was “not good enough” to say there would be a letter and sought firm assurances the report stage would not be placed on the floor of the House until the decision was available.

Earl Howe said he could not give that undertaking and the Information Commissioner had requested more time.

He said: “We have made representations to expedite the process as far as possible, but the advice I have at the moment is that it is highly unlikely if not impossible that the judgment will be delivered before we are due to go into the report stage of the bill.

He added he would provide updates when available as he did not wish this to be a “closed process”.

The exchanges in the House of Lords came as peers embarked on the 15th and final day of the marathon committee stage consideration of the government’s Health and Social Care Bill.

The bill completed its committee stage and the government could face fresh battles when it returns for the report stage in the new year.