The Keep Our St Helier Hospital organisation also questions whether any "tough questions will be answered."
"As far as Keep Our St Helier Hospital campaigners are aware, the meeting about St Helier Hospital's future in Wallington is still going ahead," said the spokesperson.
"In light of media reports this week in which Healthwatch responded to concerns from local residents that the meeting is not politically neutral, we still have concerns that this will be an event that is stage-managed by local Liberal Democrats.
"Healthwatch claims it used Tom Brake's office for administrative support but this has resulted in RSVPs and undemocratic questions in advance being submitted via Tom Brake's website. With a Liberal Democrat-heavy panel and the whole event being administered via a Liberal Democrat MP's office, KOSHH campaigners will be very interested to see how tonight's meeting pans out and whether any tough questions will be answered.