Canberra, Aug 8 (IANS): Australian public servants will be barred from criticising the government on social media under a plan revealed on Tuesday.

The social media guidelines of the Australian Public Service Commission were updated to ensure the impartiality of public servants in their roles, Xinhua reported.

Under the new rules, employees could be sanctioned for sending private e-mails critical of the government, liking critical social media posts and failing to exclude themselves from posts made by others about the government.

"If you 'like' something on a social media platform, it will generally be taken to be an endorsement of that material as though you'd created that material yourself," the updated guidelines said.

"Sharing a post has much the same effect.

"Doing nothing about objectionable material that someone else has posted on your page can reasonably be seen in some circumstances as your endorsement of that material."

The changes have been labelled a serious concern by union bosses and lawyers have raised concerns that it could be constitutionally invalid.

"If you e-mail your mates something and they put it on social media, then your job might be under threat," Nadine Flood, secretary of the Community and Public Sector Union, said.

John Lloyd, Australia's Public Service Commissioner, defended the policy, saying the new guidelines were not more restrictive than the old.

"It's very little change, just amplifying it, making it easier to understand. We were really keen that staff could follow it," Lloyd said.

"We are just telling people to be careful about what they post and how they manage their social media," he said.