'Crucify "no" voters' has been graffitied on a Melbourne church in the latest call to violence during Australia's increasingly toxic same-sex marriage postal survey.

Churchgoers arrived at Waverley Baptist Church in Wheelers Hill on Sunday morning were horrified to find the threat branded across the walls of the church building along with a plea to 'vote "yes"'.

Senior pastor David O'Brien said: 'We all woke up to see the awful vandalisation of our church. It's disappointing to see these things and it was a shock to all of us.'

He added that although the church's leaders have openly backed the 'no' side, some members of the congregation worked for the 'yes' campaign and the church accepted everybody.

'We have people at the church who have worked for campaigns on both sides,' he told the Herald Sun.

'While there has been heated discussions in the community, we have never received threats before.

'This was completely out of the blue.'

It comes as the rhetoric around Australia's public poll to guide Parliament on whether to legalise gay marriage becomes more and more aggressive and divisive.

Last week the Anglican Diocese of Sydney revealed it had donated $1million to the 'no' campaign to the horror of many church leaders in the area.

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.'

But O'Brien insisted he would not succumb in the wake of the threats to his church.

'We will not yield to hate,' he said.

'We will continue to love all, gay or straight, or whatever, and will continue to care for people no matter what and to teach the principles of good and moral behaviour that benefit all.'