In a warning to the state government, Labor Council secretary Michael Costa said the time for "considering legislation" is over and unions are "taking action".
"The state government has been considering legislation for 18 months so unions are stepping up the pressure for the introduction of laws to ban employers from secretly snooping on workers' e-mails," Costa said.
"We believe the Internet is a public asset, not something an employer owns. Employers should trust their workers to use this technology responsibly rather than spying on them as though they are some kind of internal enemy."
The Labor Council is making representations to the NSW Industrial Relations Minister John Della Bosca to argue that because it is illegal to tap telephone conversations the same rules should apply to e-mails.
"Phone conversations do not belong to an employer; it's time for the law to catch up with recent technological advances," Costa said.
"We also want to guarantee trade unions have access to office e-mail to distribute relevant information to members."
Internationally, the UK government is facing a human rights challenge in the European Court of Human Rights by public sector employees who oppose workplace monitoring.