Trocaire and the Irish Congress of Trade Unions have combined to open a pre-Christmas consumer campaign against exploitation in the toy industry.
Barbie dolls, Fisher Price toys and Pokemon video games are among the items targeted as they are made in Asia by workers who lack union representation and have few statutory safeguards.
"The aim of the campaign is to get major toy companies to take responsibility for improving the conditions of workers," said Trocaire's campaign officer, Ms Caoimhe de Barra.
She estimated there were a million workers, mainly women aged 17 to 25, working in China's free trade zones alone for multinational toy companies.
"We are not asking people to boycott the toys but we are asking them, when they buy a toy, to contact us and get a postcard they can send to the supplier.
"Multinationals can demand that factories from which they buy goods allow their workers to unionise. It is not ideal but it is a step along the way."
Mr Jack O'Connor, a SIPTU regional secretary, said his members would be receiving copies of the postcard and would be asked to use them to heighten awareness of the problem.
He said many companies had announced codes of practice in response to consumer pressure but very few had put these into practice.
The cards are available from Trocaire and the ICTU. They are addressed to the chief executives of the main companies involved.
These include Mattel, Hasbro and Disney. The latter does not produce toys but franchises products to manufacturers.