He told the committee about the concerns of people who had contacted the Scottish Disability Equality Forum about the reforms in the bill: "Some of the calls we are getting are devastating to hear, so the effect on the disabled person is... some people are becoming suicidal simply because of the thought of them."
The UK government has said the legislation aims to "make work pay".
It sets out plans to ensure people in work are better off than the unemployed.
A "universal credit", sanctions for those turning down jobs, and a cap on benefits paid to a single family, are among the changes outlined.
Planned housing benefit curbs for the jobless have been dropped but tenants 'under-occupying' homes face cuts.
Mr Robertson accused the Westminster government of being like a "blind rhinoceros running wild" that has to make 20% cuts immaterial of the consequences for disabled people across UK.
Pam Duncan from Inclusion Scotland told the committee: "The UN Convention on the Rights of the Disabled People, says under Article 19, that disabled people have a right to live in the community, yet this is grossly threatened by the reforms we see in front of us."
When the panel of guests was asked by SNP MSP Bob Doris if they would back the Scottish government taking a stand against the legislative consent motion on the Welfare Reform Bill, Ms Duncan and Mr Robertson, as well as Richard Hamer from Capability Scotland all said they would.
Carolyn Roberts from the Scottish Association for Mental Health (SAMH) said she was concerned a vote against the legislative consent motion could have a negative impact.
Ms Roberts had earlier expressed trepidation about the "substantial impact on mental health problems" of the reforms.
She said the move from Disability Living Allowance (DLA) to Personal Independence Payment (PIP) would lead to a focus on physical illness and her organisation was pushing for an amendment which would mean people with "fluctuating conditions" could qualify for PIP and thus not rule out people with severe mental health problems.
In the second part of the session, which can be viewed below, Neil Couling from the Department of Work and Pensions tells the Health Committee the Scottish government needs to pass the legislative consent motion for the UK Welfare Reform Bill or pass its own legislation.
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