Supporters of a public inquiry into how more patients than expected died at Stafford Hospital have said they are anticipating an announcement later.
There were more than 400 deaths between 2005 and 2008 than would be expected at the hospital.
Cure the NHS , a group of people whose relatives died at the hospital, are going to the Houses of Parliament on Wednesday.
Conservatives had supported public inquiry demands before the election.
A previous inquiry into the running of the hospital, chaired by Robert Francis QC, concluded that patients were routinely neglected at the hospital after managers became preoccupied with cost-cutting and targets.
The inquiry was held behind closed doors as Mr Francis pointed out much of the material he would have to consider would contain sensitive and confidential medical information.
The Labour government had also said it would not hold the inquiry in public.
A Healthcare Commission report in March 2009 highlighted the unusual amount of deaths.
Criticisms included receptionists carrying out initial checks on patients.
The Care Quality Commission, which replaced the Health Commission, has said care is now safe although some problems persist over staffing and equipment.
The chief executive and chairman in charge during the period in question have been replaced and the General Medical Council and Nursing and Midwifery Council are investigating some staff involved.