Former Treasurer Peter Costello has fired a damaging salvo at the Abbott government just weeks out from its second budget, describing its approach to taxation as a 'morbid joke'. Ever since the government released his tax discussion paper calling for a 'lower, simpler, fairer' system there has been nothing but suggestions for taxes that are higher, more complicated and less economic, the former Liberal treasurer in an opinion piece in the Daily Telegraph. 'Lower, simpler, fairer is looking like a morbid joke,' Mr Costello said on Tuesday, citing a proposed bank deposit tax and a push for a greater contribution from multinational companies. Peter Costello slammed the Abbott government, describing its approach to taxation as a 'morbid joke' Treasurer Joe Hockey was not impressed with the Costello critique, lamenting the fact his Liberal predecessor had more tax revenue to use during the Howard government years . 'The government needs to restart the conversation about getting taxes down, not up.' He also slams Labor and the Greens, saying using the tax system to re-distribute income would trap Australians in poverty. 'The tax system is there to raise government revenue at the lowest cost in the most efficient way doing the least damage to the economy.' Treasurer Joe Hockey was not impressed with the Costello critique, lamenting the fact his Liberal predecessor had more tax revenue to use during the Howard government years. 'If I had the same revenue as he had, then I'd be getting $25 billion extra each year to spend on things,' he told Sky News from New York, pointing to the abolition of the carbon and mining taxes. 'Everyone's entitled to give free advice and frankly, that's what it's worth - it's free advice. The Abbott government is due to deliver its second budget on May 12 . Assistant Treasurer Josh Frydenberg praised Mr Costello as a 'very distinguished' former treasurer, but said the government had reduced the overall tax take and a small business tax cut was on its way . 'I would suggest that people stop looking back to what it was and focus on the challenges of today and tomorrow, no matter who they are.' Assistant Treasurer Josh Frydenberg praised Mr Costello as a 'very distinguished' former treasurer, but said the government had reduced the overall tax take and a small business tax cut was on its way. The coalition was also having to deal with lower commodity prices than the Howard government enjoyed, he told ABC radio. In an opinion piece, Fairfax economics editor Peter Martin argued that Hockey had inherited economic problems created by  superannuation changes Costello introduced when he was treasurer. Mr Martin labelled 2006 budget changes which saw super payouts become tax free for the majority of Australians aged over 60 as 'stupid' and 'expensive'. He quoted economist Saul Eslake who labelled the change 'one of the worst taxation policy decisions of the past 20 years'.
Peter Costello slammed government pledge for 'lower, simpler, fairer' taxes .
The former treasurer singled out Joe Hockey's proposed new bank tax and Josh Frydenberg's push for revenue from multinationals .
Mr Hockey hit back at Mr Costello, saying he wished he had the tax revenue the former treasurer had when the Coalition was last in power .