Prime Minister Malcolm Turnbull has said there will be a fairness test applied to any changes to taxes.

Speaking at an economic outlook conference in Melbourne on Thursday, Mr Turnbull called for a “good, open discussion” on tax reform.

“It is not enough to persuade the public that your motives are good,” he said.

“You also have to demonstrate that you’ve taken decisions in a thoughtful, open, consultative way – that you’ve carefully weighed up the various options and arguments.”

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He also described the need for a “culture that embraces change” to see the reforms through – which, if they include tax increases, will be strongly opposed by the ALP.

The speech followed growing calls for tax reform.

Earlier this year, NSW Premier Mike Baird proposed raising the GST from 10 per cent to 15 per cent, coupled with income tax cuts.

More recently, Federal MP David Gillespie put forward modelling that suggested the Commonwealth Government could make an additional $130 billion in 2017-18 by expanding and raising the GST.

An increase in the GST would harshly impact the poorest families, according to the Australian Council of Social Service. Photo: Shutterstock

Shadow Treasurer Chris Bowen said a GST increase would “make Australia’s tax system more regressive”.

“Malcolm Turnbull’s been doing a lot of talking lately, gave a speech today, couldn’t bring himself to utter the letters GST but what we are seeing the more and more evidence that the Turnbull-Morrison plan is simply to hit low income earners the hardest,” he told media in Melbourne.

“If Mr Turnbull wants to have a debate, give us the plans an we are happy to debate our plans and his plans but we have ours on the table, Mr Turnbull does not.”

‘A recipe for inequality’

A leading welfare group released a study criticising any increase to the goods and services tax, on Thursday.

A study from Australian Council of Social Service (ACOSS) found a 5 per cent increase to the GST would disproportionately impact the poorest families.

According to the National Centre for Social and Economic Modelling data, the lowest 20 per cent of income earners would be 7 per cent worse off, while the highest 20 per cent would pay just 3 per cent more.

ACOSS chief executive Cassandra Goldie said even if the GST hike led to lower personal income taxes, it would “require a major compensation package”.

“[It] is a recipe for more inequality, not a stronger economy,” she said.