The ex-footballer, who is nicknamed "Fossil" on the show, unloaded on the AFL and said the sporting body had no right to tell people how to vote.
"You are nothing more than obsequious, fawning, sycophantic political wh***s. You have no right to get involved in political messages," Newman said on the Nine Footy Show on Thursday night.
"If this was about the AFL putting Yes on the football about climate change, or save the whales, or greenhouse emissions or whatever, I would have exactly the same opinion," Newman added.
"But who in the hell are these people at the AFL who are telling the football public what they should do in their lives and who they should vote for in any political agenda. Who are you?"
"Who gives you the right to tell people and to put on the football what people should do."
Co-host Eddie McGuire fervently rebuked Newman's rant and said the AFL was a leading national organisation that was welcoming equality.
The AFL logo at the sporting organisation’s Dockland headquarters in Melbourne showed a striking change on Wednesday morning with the word ‘Yes’ splashed across it.
"The AFL is committed to equality and diversity, and we support the rights of all Australians to live, work and play free from discrimination," the AFL posted on Twitter.
AFL chief Gillon McLachlan expressed his support for marriage equality on Tuesday night.
"This is something that actually talks to a core value of ours, which is actual equality, that people, based on race, gender, sexuality, shouldn't be discriminated against," he told Fox Footy show AFL 360.
Prime Minister Malcolm Turnbull said it was a matter for the AFL which causes it supports.
"I'm not going to tell the AFL or any other organisation how to run their affairs," Mr Turnbull told 3AW on Friday.
"The AFL has always had a very forward leaning approach on social issues, whether it's multiculturalism or reconciliation.
"They have always been a very socially progressive organisation and taken a strong stand on the same sex marriage issue for a long time."
The AFL has previously supported campaigns against racism and street violence, and has promoted the cause of women and indigenous people in the game.
