However, he did not attend, a spokesman confirmed.
"It's a departmental matter."
State Services Commissioner Iain Rennie - criticised for his handling of the Sutton saga - also chose to keep his distance.
"This is a private function for Cera staff who wish to attend," a State Services Commission spokeswoman said.
Meanwhile, the woman whose allegations led to Mr Sutton's resignation has been working "as normal" but had decided to take yesterday off. She has remained anonymous throughout the scandal.
"She's not a big fan [of the farewell] but she hasn't made a big deal of it," said one source. "There are people in the [Cera] building who aren't happy that it's actually happening and there will be plenty who aren't attending."
A Cera spokeswoman said the afternoon tea was an opportunity for staff to farewell Mr Sutton. She said the private function was held away from Cera's offices and no taxpayer funding was used for it.
"The purpose of the afternoon tea is to recognise the service Roger has given to Cera and the recovery, and to respond to the wishes expressed by some staff to have an opportunity to farewell him.
"The matters which led to Roger's resignation will not be discussed at the function."
Mr Sutton told RadioLive the farewell was an opportunity for him to "look a lot of people in the eye and say thank you for working so hard and being so dedicated and supporting me through three and a half years of really hard work".
His role as chief executive officially ends tomorrow.
