Tyson Duval-Comrie is a 25-year-old male with an intellectual disability.

Tyson Duval-Comrie wants a pay rise from $1.77 to $3.54 an hour. Photo: James Boddington

Lawyers acting for thousands of underpaid intellectually disabled workers will lodge a court application on Monday to block the Abbott government's scheme to tackle the underpayments.

Legal firm Maurice Blackburn will file the Federal Court action in a bid to stop 10,000 intellectually disabled employees at sheltered workshops signing away their legal rights to sue the government for back pay.

Some of the employees involved in the case are paid less than $1 an hour.

The Abbott government last week announced it would make a one-off payment in July to the underpaid employees.

The amount was not specified, but those who agreed to the payment would waive rights to sue for potentially a much larger amount.

The payment pledge followed a court decision in 2012 that found workers at sheltered workshops had been underpaid for several years, in breach of the Disability Discrimination Act.

The government's proposal to set up the fund came just weeks after a class action was lodged by legal firm Maurice Blackburn in December seeking to recover the underpayments.

Social Services Assistant Minister Mitch Fifield said last week that the one-off payment to sheltered workshop staff would ''deliver certainty'' for them and their families and carers, with minimal disruption.

But Maurice Blackburn industrial relations head Josh Bornstein condemned the government's plan as immoral.

He said it attacked a highly vulnerable group of workers. ''This government is attempting a shakedown of intellectually disabled people,'' Mr Bornstein said.

The move followed the government's changes to remove superannuation top-up payments for low-paid workers, and also after it had changed plans to increase wages for aged care and childcare workers, he said. ''There is a pretty strong pattern emerging already of this government attacking the rights of the lowest paid in our community.''

Under laws for the workshops, many disabled staff are legally paid about $1 to $2 an hour despite Australia's supposed minimum wage being $16.37 an hour.

The application to the Federal Court on Monday will demand that all communication between the government and disabled workers involved in the class action be supervised by the court.

There are more than 300 Australian Disability Enterprises, formerly known as sheltered workshops, employing about 20,000 disabled people in work including packaging, manufacturing and cleaning.

Among those involved in the court battle over pay for intellectually disabled workers is Tyson Duval-Comrie.

The 25-year-old, who has an intellectual disability, is employed at a centre that undertakes packaging tasks such as placing sugar sticks in boxes and screwing lids on herb containers.

Mr Tyson's wage is $1.77 an hour, which, if his side wins the court battle, would rise to $3.54.

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