Sinn Féin and the Labour Party are to put forward their first joint Private Members' motion in the Dáil this week.
The motion will call on the Government to introduce legislation to force employers to treat workers recruited through employment agencies on the same basis as permanent staff.
Sinn Féin employment spokesman Arthur Morgan said yesterday that agency workers were often employed on inferior pay and conditions. Such developments were unfair, and could also undermine existing arrangements for permanent staff.
The Sinn Féin/Labour motion says that without legislation which ensures that agency workers are subject to the same terms as directly-employed workers "employers will always be tempted to cut corners on terms and conditions and casualisation, and exploitation will take hold".
The motion calls on the Government "to immediately introduce legislation to protect the equal rights of agency workers, compared to their permanent counterparts, whereby employment agency workers would be subject to a collective agreement specifying terms and conditions of employment".
It says such legislation should specify a maximum period beyond which the worker must become a direct employee.
Mr Morgan said the issue of agency workers was very important at this time as it would be a very significant feature in the new national pay talks which are to get under way in the weeks ahead.
The Irish Times understands that legislation to be published by the Government this month will stipulate that workers recruited through agencies cannot have inferior terms and conditions to those set out in registered employment agreements where they apply. Such agreements are registered with the Labour Court.
The Government will also publish a separate Bill to regulate the operation of employment agencies.