"I wish I was not here doing this today," Taylor told the committee. "I would rather have my son Ross alive."
She asked MPs to put politics aside in election year and form a cross-party consensus on the issue.
"I plead with you today to listen very carefully. Do not use this information today to make idle election promises whilst our people are dying every day from poor care."
Taylor gave a long list of problems with the sector. Services were understaffed and fragmented, there was no official suicide prevention programme, money given to district health boards did not filter through to primary care, many mental health files were hand-written and difficult to access, and patients were forced to repeatedly tell their stories as they moved through the system, often re-victimising them.
Unless patients were severely ill, they were unlikely to get counselling or therapy. Those with milder conditions were usually given pills by a GP and never received counselling.
One GP had told Taylor that demand for counselling sessions outweighed services by a factor of 20. Some universities had as few as eight fulltime counsellors for up to 20,000 students.
"There is an unprecedented agreement between patients, families and the workforce that mental health services are broken," Taylor said.
The last review of the sector was the Mason Inquiry in 1996, which led to the formation of the Mental Health Commission.
The commission was disbanded under the National-led Government in 2012. The Green Party last year called for it be reinstated following a series of suicides in residential care.
Health Minister Jonathan Coleman hinted last week that there could be a funding boost for mental health initiatives in tomorrow's Budget. Finance Minister Steven Joyce would not give anything away today, telling reporters to wait until tomorrow.
Labour announced its mental health policy earlier this month, which would trial a programme in which dedicated mental health teams were placed within GP practices.
Leader Andrew Little said it was based on advice from mental health workers, and aimed to fill a gap in care for people with mild to moderate mental health needs.