Ann Clwyd has called for a fresh review into Welsh hospitals, saying death rates in "one or two hospitals in Wales are higher than at the Mid Staffordshire hospital."
"That should be a very clear signal that something is wrong. Somebody ought to be analysing it," she said.
Fresh claims of serious neglect have been uncovered by a special ITV News investigation at a hospital already at the centre of a major police investigation and an independent review ordered by the Welsh Government.
The Cynon Valley MP published a report into the way complaints int the NHS in England in October and has called for an inquiry into Welsh hospitals with higher-than-average mortality rates.
She has been demanding better treatment of hospital patients since she complained that her own husband was neglected before his death at the Heath Hospital in Cardiff last year.
Figures obtained by ITV News have revealed a significant rise in the number of complaints made and upheld against the Abertawe Bro Morgannwg University Health Board in Wales.
- 2008/09: 17 complaints - 4 upheld
- 2009/10: 46 complaints closed - 11 upheld
- 2010/11: 51 complaints closed -14 upheld
- 2011/12: 60 complaints closed -18 upheld
- 2012/13: 87 complaints closed - 34 upheld
- 2013/14: On the 24 January 2014 of around 76 complaints closed - 32 were upheld in whole or in part
Source: Public Services Ombudsman for Wales
The family of Dorothy Mead who died at Princess of Wales Hospital after she was admitted in 2010 have spoken to ITV News about their “fight for justice” after failings in her care.
The 82-year-old was left in the resuscitation room for almost three hours and should have been seen by a senior doctor but was not.
Michelle Chambers said: “A lot of people are grieving so badly they lose the momentum to fight and we were determined to from the outset to get justice for mum”.
Pam Davies, who worked for the Ambulance Service for more than 20 years, said: “I could recognise what was not happening there, what they weren't doing for my mother”.
The Public Services Ombudsman in Wales upheld the family's complaint.
A former nurse who worked at Princess of Wales Hospital for eight years before leaving 2009 has claimed she witnessed poor patient care on a number of occasions.
Speaking to ITV News, Glenda Rodriguez-Noza described an incident when she saw a nurse giving a patient the wrong medication:
Mrs Rodriguez-Noza, who is involved in tribunal proceedings against Abertawe Bro Morgannwg University Health Board, also said her concerns about patient care were ignored.
"An internal investigation found there was not enough evidence to support my claims and in the end it all became too stressful.
"I want to speak out because I want these people to be held to account and to stop these mistakes happening again and again".
The partner of Allan King, who died after receiving bowel surgery at the Princess of Wales Hospital in Bridgend, has claimed he experienced terrible treatment and neglect.
Dorothy Wilson explained to ITV News why she she was determined to fight for answers from Abertawe Bro Morgannwg University Health Board after his death.