The former chair of the health agency Te Whatu Ora, Rob Campbell, says it is ludicrous to expect board members to keep political opinions to themselves.
New Zealand on Air board member, Andrew Shaw, resigned on Tuesday after criticising the Deputy Prime Minister Winston Peters.
On social media, Shaw described Peters as malicious and untruthful. He apologised on tuesday and resigned with immediate effect.
New Zealand on Air says Shaw accepts it was wrong to publish his personal political views.
Earlier this year Rob Campbell was sacked for a similar breach of conduct when he criticised the National Party's Three Waters policy.
Campbell spoke to Ingrid Hipkiss.