As the government prepares to deliver its first budget, Prime Minister Tony Abbott’s approval rating has fallen significantly and, for the first time, Opposition Leader Bill Shorten is preferred PM for more Australians, according to new polling from Essential Research.

Abbott how has a -20 point approval rating, with 55% of voter disapproving of his performance and only 35% approving, significantly down from 41%  approval in April (in April 47% disapproved of his performance). Approval splits heavily on party lines, but Abbott’s problems with female voters continue: he trails among men 39%-54% but among women 32%-57%. Shorten has marked time in approval — his 35%-37% split is little different to April’s 34%-38%; Shorten lags badly among “other” voters 27%-44%, but not as badly as Abbott (19%-76%). Unlike Abbott, men and women appear to feel the same about Shorten.

But on preferred prime minister, Shorten has reversed Abbott’s 10-point lead in April, 42-32%, to lead the Prime Minister 37%-36%, the first time he has led Abbott. Abbott’s support is slightly softer among women, but interestingly Shorten’s support was particularly strong in Queensland (44%) while Abbott was stronger in his home state of New South Wales (42%).

Essential also asked about voter support for a range of Commission of Audit and pre-budget proposals. The strongest support was for university graduates to begin repaying loans sooner, once they reach minimum wage (support 50%, opposition 24%) and forcing single Newstart recipients to relocate away from home (44%-31%) and receive Youth Allowance (39%-31%). The least favoured proposals were raising the pension age (18% to 62%) and raising interest rates on student debt (13%-63%). Privatisation of bodies like Australia Post, the Royal Australian Mint and Snowy Hydro were also strongly opposed, and even disliked by Liberal voters, although the latter were almost evenly split about privatising Snowy Hydro. Medicare co-payments were also opposed 55%-25%, although more Liberal voters supported them than opposed, but there was a big gender gap on that issue: women (60%) opposed co-payments much more than men (49%).

Asked who was most favoured by the policies of each side, the Coalition rates strongly as the party of the rich, although neither side performed well on “treating all groups equally”.

Sixty one per cent of voters also think big business doesn’t pay enough tax (including 56% of Liberal voters); 59% don’t think high-income earners pay enough tax (57% of Liberal voters); 61% don’t think mining companies pay enough tax; 68% think large international corporations don’t pay enough tax, and 56% think religious organisations don’t pay enough tax, with no difference apparent between Labor and Coalition voters.

On voting intention, the Coalition remains on 40%; Labor’s primary vote has lifted a point to 39%; the Greens have lost a point to fall to 9%; Palmer United is on 5%. The two-party preferred outcome remains unchanged on 52%-48% in Labor’s favour.