Prime Minister Malcolm Turnbull made an "unambiguous" offer to provide public funding for opposing sides in the same sex marriage plebiscite, one of Australia's most senior Anglican leaders says.

The Federal Government is considering whether to provide funding for both the "yes" and "no" camps, if legislation to establish the plebiscite is successful.

A spokesman for the Archbishop of Sydney Glenn Davies said Mr Turnbull made the remarks at a meeting of church leaders earlier this year.

"It is the Archbishop's clear recollection that the Prime Minister, in words that were unambiguous, stated that funding would be available to both sides on a similar basis to the republic referendum, thought the exact amount was not discussed," the spokesman said in a statement.

"The promise was later raised at a smaller meeting with [Attorney-General George] Brandis in March, who then asked what funding was appropriate, to which the Archbishop replied: the same amount as in 1999, CPI adjusted."

The "no" camp is pushing for about $10 million to be provided to both sides of the plebiscite campaign.

However, one of the key demands from the Federal Opposition is that no public funding be provided to either side in exchange for their support of the plebiscite.

Brandis promises 'strict funding equality'

Senator Brandis told reporters in Brisbane there had been a "very thorough" process of consultation, and that both sides of the argument have been told they will be treated with "strict equality".

"I've made it clear that if there is public funding, it will be on the basis of equality," he said.

Senator Brandis said the issue of public funding was a matter for Cabinet and the party room, but stressed the Government was keen to minimise the cost to taxpayers.

"We want to keep the cost of the plebiscite as low as it can be kept, this is obviously an expensive exercise, but we think an appropriate exercise because whatever the decision of the plebiscite is, it's very important that the entire community own it," he said.

The comments have been echoed by Education Minister Simon Birmingham.

"It's important that the plebiscite provides an accurate indication of the will of the Australian people but also does so at the lowest possible cost, so all of those factors will be considered I'm sure during the appropriate Cabinet and partyroom discussions," he said.

"I have only ever heard the Prime Minister say that all sides of the debate will be treated fairly and equally."

The proposed plebiscite is estimated to cost taxpayers $160 million, with Cabinet yet to decide on the final wording of the proposal.