The Turnbull government's big-spending, higher-taxing second budget has delivered a poll boost to the Coalition's political fortunes, with a big majority of voters backing its tax on banks and the increase in the Medicare levy.

But Labor still holds a strong 53 per cent to 47 per cent lead in the two-party preferred vote, based on 2016 election preference flows, though it has slipped back from the massive 55 per cent to 45 per cent lead in the March Fairfax Ipsos poll.

On the crucial question of whether the budget was fair, 42 per cent of voters have given the document a tick, whereas 39 per cent of people said it was not, a net positive result of three percentage points.

In comparison, voters gave the 2014 budget a net score of minus 30 percentage points, the worst result in 21 years of the question being asked. The 2015 budget had a net positive score of 19 percentage points, and the 2016 budget had a net negative score of six percentage points, while the former Labor government's budget typically enjoyed strong support as being fair overall.