Malcolm Turnbull says he would welcome John Howard's help in drafting legislation for same-sex marriage should the 'yes' vote win the postal survey.
The former prime minister is concerned the government has yet to detail protections for parental rights, freedom of speech, and religious freedom.
"If a 'Yes' vote is recorded there will be overwhelming pressure to 'move on', legislate as quickly as possible, and then put the issue behind parliament," Mr Howard said.
"There will be scant opportunity for serious consideration of protections in the areas I have cited."
Mr Turnbull noted Mr Howard did not make a submission to a parliamentary committee looking into the process, but would like to draw on his experience.
"We will welcome John Howard's contribution to the fine-tuning of that exposure draft bill and its improvement," he told Sky News on Friday.
Mr Turnbull said the private member's bill will have religious protections included.
"But of course it then has to go through the parliament."
Cabinet minister Christpher Pyne said "of course" the government wasn't washing it hands of its responsibility, as Mr Howard has asserted.
"We will protect the freedom of speech of people and of course the rights of people to choose whether they do or don't marry couples," he told the Nine Network.
Mr Pyne said Mr Howard is allowed to campaign in the debate as much as anybody else.
"It is not a question of John Howard v Malcolm Turnbull, or anybody else quite frankly, it is whether people believe that two people who love each other should be able to get married," he said.
Labor frontbencher Anthony Albanese said opponents of same-sex marriage are raising every issue except for the one being asked of Australians.
"Whether two people who love each other can give that commitment in front of friends and family," he said.
The Australian Bureau of Statistics is aiming to get the survey forms out to 16 million voters by September 25, with the first arriving in mailboxes earlier in the week.
