A memo issued by the Commission's acting secretary Jacques Gedeon said requests to use social media must be approved by the PSC Secretariat before access is enabled.
RNZI correspondent Heather Maraki said work was getting underway to implement the social media restrictions, which had already provoked a strong response from public servants.
"There's been a lot of reaction from Facebook," she said.
"A lot of them have been complaining that they are also there to see what's happening, commenting, giving their thoughts about all the issues that are being raised on social media and so forth. But the PSC is their employer and they have the right to do anything."
Heather Maraki said many government workers spend time on social media sites during working hours and the Public Service Commission was trying to limit their access so they could concentrate on their work.