The ratification of the Lisbon Treaty will help to advance workplace rights, according to the Charter Group.
It is made up of trade unionists and other campaigners who are supporting a 'Yes' vote in the poll on October 2.
The group is launching a 24-page booklet later on how it believes Lisbon will help protect employment.
The People's Movement will also launch its campaign later, calling for a 'No' vote to Lisbon.
The Unite trade union has called for a 'No' vote however, saying that the treaty will damage workers' rights.