Some of Sydney's Anglican clergy are in open rebellion against their diocese's decision to donate $1 million to the campaign against same-sex marriage.

The Archbishop of Sydney announced the move on Monday, adding he made 'no apology' for backing the 'no' campaign in the country's upcoming postal poll to advise the government on whether to legalise gay marriage.

'The stakes are high and the cost is high,' Glenn Davies told a Sydney synod of churches on Monday. 'Yet the cause is just and it is a consequence of our discipleship to uphold the gift of marriage as God has designed it – a creation ordinance for all people.'

The funds came out of the largely conservative area's Diocesan Endowment fund.

But Anglican clergy are furious at the decision with several highlighting the variety of views on the controversial topic within the Church and saying the money could have been better spent elsewhere.

Rev Dave Smith, parish priest at Holy Trinity in Dulwich Hill, said he was 'shattered' by the decision.

'I think there's a degree of shock [among the congregation]. I think they are taking it pretty hard,' he said according to the Sydney Morning Herald.

Father Andrew Sempell of St James' said he was 'surprised' by the announcement.

'There was no consultation, there was no open debate – and therefore no transparency in the decision,' he told Fairfax Media.

'We haven't let go of Christendom all that much. We still think that we have a right to tell people what to do. This is one of the reasons we're on the nose.'

He accused the diocese of poor financial management in the past, saying 'they did everything wrong that you could possibly do', adding: 'Which sort of begs the question: why are they throwing money around like this?'

Even conservative ministers who back the 'no' campaign criticised the scale of the donation.

Rev Michael Paget of St Barnabas on Broadway described the donation as 'out of proportion' amounting to 'poor financial stewardship' and was close to 'indefensible'.

Melbourne journalist and author Dr Muriel Porter, who has served on the Anglican Church of Australia's national General Synod for 30 years, said she was 'not surprised, but I am shocked' by the donation, describing it as 'an extraordinary use of church money'.

'People will just think, for heaven's sake, that they are out of touch,' she told Buzzfeed. 'It's the way the church has treated women. The Anglican Church's opposition to the full equality of women; their decades-long opposition to divorce and remarriage. That did huge damage to people.

'It hadn't just been the sex abuse crisis that damaged the churches, it's their attitudes to ordinary people and their ordinary lives.'

Both sides in Australia's increasingly toxic debate over gay marriage claim to have been outspent by their opponents.

Executive director of the Equality Campaign, Tiernan Brady, said the donation was evidence that 'opponents of equality have radically outspent the Yes side'.

He told The Australian: 'But what they have in buckets of cash, we make up with in hundreds of thousands of Australians making the case for a fairer, more just and inclusive society.'

However despite repeated claims from the Yes side they were being outspent, it emerged last month Qantas chief executive Alan Joyce also personally donated $1 million to the campaign in support of same sex marriage.