Business groups have bristled at plans to let workers unplug and unwind once their shifts are finished.
Employees would have the right not to be contacted outside office hours under workplace changes being considered by the federal parliament.
The "right to disconnect" is expected to be included among proposed amendments to the Fair Work Act, after being endorsed by a Senate committee.
The rules would be aimed at ensuring "clear expectations about contact and availability in workplaces".
Business Council chief executive Bran Black warned such laws could have unintended consequences.
"If employees and employers are banned from sending emails to each other outside of working hours, it could grind national businesses, operating in different time zones, to a halt," he said.
"It could also severely hinder flexible working arrangements if employees couldn't email their colleagues outside of traditional hours."
Mr Black urged Workplace Minister Tony Burke to make changes to the proposed amendment.
"Everyone deserves to be able to switch off at home, though it's really important to get the balance right here, given people are now wanting more flexibility and to work different hours and in different ways," he said.
Right to disconnect laws exist in several nations including Italy, France and Ireland.
Mr Burke has been locked in negotiations with the Senate over wide-ranging workplace changes, with legislation expected to be introduced within weeks.
Other measures include allowing for casual staff to transition into permanent positions, along with greater protections for gig economy workers.
The coalition voted to strongly oppose the workplace laws at a joint party room meeting on Tuesday.
