Mr Abbott's trustworthiness rating now stands at a record low of 35 per cent after Joe Hockey's first budget, which has also shredded his standing as preferred treasurer.

The budget's mix of harsh cuts and new imposts, including the $7 GP co-payment and an increase in fuel tax, have wiped out a 17 percentage point advantage Mr Hockey had over shadow treasurer Chris Bowen in March.

That collapse comes after weeks of policy inertia by the government, which delivered a budget containing measures expressly ruled out before the election and for which it has since done little to build a case.

The Treasurer vacated the budget battleground during the carbon tax argument, only to return from holidays threatening to bypass Parliament with harsher cuts unless the new Senate rolled over.

The nationwide Fairfax-Nielsen survey of 1400 people was taken from Thursday, July 17, to Saturday, July 19, and shows Labor well ahead of the Coalition on two-party preferred terms at 54 per cent to 46 per cent, based on 2013 preference flows. That amounts to a swing to Labor of 7.5 per cent since September.

The survey period straddled the deaths of 37 Australian citizens and residents aboard Malaysia Airlines flight MH17, which was shot down over eastern Ukraine on Thursday night.

Mr Abbott's assured handling of the atrocity in the hours since has been widely commended but has not been reflected in this poll result.

His approval rating has improved mildly since the June survey but he remains deeply unpopular with a net rating - the percentage of those who approve of his performance minus those who disapprove - sitting at minus 18 per cent.

That is a seven-point improvement but he still trails Mr Shorten. The Opposition Leader's net approval slipped into negative territory but is much healthier at just minus 3 per cent.

On preferred prime minister, Mr Shorten continued to lead by 5 per cent at 46 per cent to 41 per cent.

Pollster John Stirton said the result was a bad one for the government and especially for Mr Abbott.

''Mr Abbott fell behind in May 2014 after eight months in office, faster than any previous prime minister with the exception of Paul Keating who started out behind,'' he said.

''Julia Gillard was preferred PM for her first 13 months in office … Kevin Rudd was never behind and John Howard was preferred PM for 21 months after being elected.''

When respondents were asked to say whether Mr Abbott or Mr Shorten was a ''strong leader'', the Prime Minister had a seven-point lead over his rival. But that same strength shows up in negative ways, with just 38 per cent of voters viewing him as open to ideas compared with 58 per cent for Mr Shorten.

On competence, Mr Shorten leads Mr Abbott by five points, 57/52, and Mr Shorten has a 10-point lead on the question of trustworthiness, 45/35.

Both men were seen as safe from internal challenge, with about two-thirds of voters believing they had the confidence of their parties.

However, Mr Abbott was way ahead of Mr Shorten on the issue of ''vision for Australia's future'', leading 54 to 38 per cent.

Just 28 per cent of voters regard Mr Abbott as open to influence by minority groups compared with Mr Shorten, who is seen as malleable by 42 per cent.

Mr Abbott also leads on foreign policy competence, 43/38, and decisively on an ability to make things happen, where he is ahead by 22 points on 58/36.

On economic policy, the two are evenly poised but on sensitivity to social policy the Opposition Leader scored best at 58/34.