Twenty mental health experts have written a report, 'Running on Empty'.
They include Rethink director of communications Paul Corry, SANE chief executive Marjorie Wallace MBE and The BiPolar Organisation chief executive Michelle Rowett.
Its findings are based on a survey of 209 GPs and 325 schizophrenia and bipolar disorder sufferers on behalf of drugs giant Lilly UK.
The authors claim the results indicate SMI sufferers are 'receiving a worryingly sub-standard level of physical care'.
Corry said that SMI sufferers were 'offered an unacceptable level of care' and a supportive approach to treatment needed to be 'widely adopted into the everyday provision of care'.
Virgo Health PR is promoting the 'Running on Empty' initiative.
Virgo associate director Neil Flash said an executive summary of the report would be sent to every MP with the aim of getting the topic raised in parliament.
Health professionals will also be targeted and made aware that specific physical health assessments for mentally ill people are recommended by government health guidelines.
'By sending the report to health professionals we hope to encourage them to make these assessments part of nurses' routine when dealing with mentally ill patients,' said Flash.