Same-sex marriage plebiscite to cost $525m, PwC modelling shows.

By political reporter Francis Keany

A stand-alone plebiscite on same sex marriage could cost the Australian economy more than half a billion dollars, according to new research.

Modelling undertaken by accounting firm PwC says it would result in $280 million of lost productivity, on top of the cost of running the nationwide campaign, estimated at $158 million by the Australian Electoral Commission.

The cost to the community of funding the two campaigns for and against the proposal would cost $66 million, while the impact on the mental health and wellbeing of the gay and lesbian community amounts to $20 million.

PwC Australia chief executive Luke Sayers said the real cost of the plebiscite was three times what has been quoted by the Federal Government.

“Total economic costs have not been considered before and should be part of the debate on the best way to achieve a resolution to this issue,” Mr Sayers said.

The report by PwC, which was commissioned in-house, looked at three different scenarios for approaching the issue.

One involved a stand-alone plebiscite, while another looked at holding the vote at the same time as the federal election. A third option examined the financial impact of a vote in federal Parliament.

The overall cost of the vote would be reduced to $113 million if the plebiscite was held at the same time as the federal election, dropping to $17 million dollars if a vote was held in Parliament to resolve the issue.

PwC economics and policy partner Jeremy Thorpe said they analysed the impact of similar votes overseas.

“Overseas examples show that spending on the ‘for’ and ‘against’ campaigns alone can reach over $6 per voter, as happened in California,” Mr Thorpe said.

“That’s a huge waste of money that could be better allocated in our low-growth economy.”

The report stressed while there is limited data on the on the impact of mental health of Australian LGBTI people with a focus on discrimination, other studies were able to quantify the impact of mood and anxiety disorders.

It estimated 50,000 people – or around 5 per cent of the LGBTI community – would be negatively affected if a stand-alone plebiscite was conducted.

“What we find is the cost to the LGBTI community are in the order of $20 million for dealing with additional mental health costs that arise, just because of the stress and the public nature of the plebiscite,” Mr Thorpe said.

The figure stems from the estimated cost to the health system and the loss of productivity in the workplace.

The report said the estimated impact on mental health is “conservative” compared to data from local front-line services, which have reported a sharp increase in requests for assistance since 2014.

It noted while those with strong beliefs against same-sex marriage could also be impacted by the plebiscite, there was “limited evidence” publicly available to the researchers.

Prime Minister Malcolm Turnbull has vowed to push ahead with a plebiscite, following debate in the Coalition partyroom last year.

The Federal Opposition and the Greens say the issue should be resolved by a vote in Parliament, instead.

This post originally appeared on ABC News.