The Australian Greens say removing the discount on capital gains tax would generate as much as $74 billion for federal coffers over the next decade.
"Income earned in wages is fully taxed, income earned from sale of assets like property or shares is 50 per cent tax free. What is the justification for this?" deputy Greens leader Scott Ludlam says.
Releasing Parliamentary Budget Office costings in Melbourne on Wednesday, Senator Ludlam said the measure combined with his party's earlier proposals to reform negative gearing would raise $127 billion over 10 years.
Senator Ludlam said the 50 per cent discount on capital gains tax and the use of negative gearing provide tax concessions for high income earners to accumulate more wealth.
"Wage earners are left behind, are locked out of the housing market and pay higher rents. It is profoundly unfair."
Treasury's figures show the 50 per cent discount on capital gains will cost the nation $6.15 billion this financial year, the sixth biggest tax expenditure item.
The senator believes the benefits of reforming negative gearing and removing the capital gains tax discount would have flow on effects into the housing market, especially for first home buyers.
"Until the treasurer (Joe Hockey) is happy to talk about the CGT as well as the GST we'll have a tax system that drives inequality and locks young people out of affordable housing," Greens treasury spokesman Adam Bandt said.
Mortgage Choice boss John Flavell agrees more policy emphasis should be on first home buyers but doesn't believe negative gearing should be touched, saying it plays an important role in the property market.
"The tax benefits associated with negative gearing helps to make property investment more attractive to some Australians," he told AAP.
"Given that the success and strength of the housing market is critical to the ongoing health of the Australian economy, it doesn't make sense to consider removing any initiatives that help this market."
Consultants CPA Australia chief executive Alex Malley agreed that getting rid of capital gains tax and negative gearing in isolation would harm investment activity and tax revenues.
"A more holistic approach would be to encourage investment by families and others by taxing all income derived from savings at a rate lower than an individual's marginal personal tax rate," Mr Malley told AAP.
He believes such an initiative may provide the opportunity to adjust the CGT discount and make negative gearing less economically attractive, while at the same time still encouraging investment in housing, and helping improve housing stock numbers.
He also criticised the government for allowing the tax review process to drift, raising the question as to whether it is committed to genuine, broad-based tax reform.
"When the timeframes are loose and the government fails to clearly define the framework, it's not surprising that the debate is deteriorating," he said.