Labor has kept its lead in the federal election campaign but has lost ground to the Coalition in a late shift that could tighten the result on Saturday night.
Labor is ahead by 51 to 49 per cent in two-party terms compared to a lead of 52 to 48 per cent against the Coalition at the mid-point of the campaign in early May.
An exclusive Ipsos poll for The Sydney Morning Herald and The Age shows a significant gain in the Coalition's primary vote, which has risen from 36 to 39 per cent in a result that is outside the margin of error.
Opposition Leader Bill Shorten had made another significant improvement in his personal approval ratings but continues to trail Prime Minister Scott Morrison when voters are asked to name their preferred leader.
The poll also reveals that early voters are favouring the Coalition and that this could be a significant factor in the counting of votes on Saturday night, given forecasts that more than four million voters will cast their ballots early.
Almost one third of voters told Ipsos they had voted early or intended to do so.
INSIGHT INTO EARLY VOTING
Of those who had cast their votes already, 41 per cent said they were Coalition voters while 33 per cent favoured Labor, indicating higher core support for the government in this group than in the electorate at large.
On a two-party basis, those who have already voted favour the Coalition over Labor by 53 to 47 per cent.
While the race is tightening, 55 per cent of respondents said they expected Labor to win the election while only 32 per cent said the Coalition would win. Another 13 per cent were undecided.
When voters were asked to rate Mr Morrison's performance, 48 per cent approved and 43 per cent disapproved, an improvement from early May.
This means Mr Morrison's net approval rating – the difference between those who approve and disapprove of his performance – was 5 percentage points, an increase during the election campaign but well below his peak of 17 points last October.
Mr Shorten also saw an improvement in his personal ratings, with the number who approve of him rising from 40 to 43 per cent over the past two weeks and the proportion who disapprove falling from 51 to 48 per cent.
Both changes were outside the margin of error and produce a net approval rating of minus 5 percentage points, his best result since September.
PRIMARY VOTE ON THE CLIMB
The greatest rise in party support in the latest poll was a jump in the Coalition's primary vote from 36 to 39 per cent since the last Ipsos survey in early May.
This is the highest core support for the government since July, one month before the leadership spill that removed Malcolm Turnbull and installed Mr Morrison as Liberal leader.
Even so, the Coalition primary vote remains 3 percentage points below its result at the last election, exposing it to a significant swing in key seats and leaving it dependent on preference flows from Pauline Hanson's One Nation and Clive Palmer's United Australia Party.
Ipsos found Labor had a primary vote of 33 per cent, a result unchanged from the last survey but unusually low compared to other polls this week, which put the party on 36 or 37 per cent.
Ipsos found the Greens had a primary vote of 13 per cent, much higher than the party's result of about 10 per cent at the last election.
Pauline Hanson's One Nation has a primary vote of 4 per cent while Clive Palmer's United Australia Party is on 3 per cent.
PREFERENCE FLOWS COULD BE CRUCIAL
The two-party result is based on preference flows at the last election, allocating second preferences from One Nation and United Australia Party using a split of 53 per cent to the Coalition and 47 per cent to Labor.
When voters were asked how they would allocate their preferences, the survey produced the same result of 51 to 49 per cent in Labor's favour in two-party terms.
The poll is based on 1842 respondents who were surveyed from Sunday to Wednesday, in the wake of Mr Morrison's official campaign launch, the announcement of his scheme to guarantee part of the loans made to some first home buyers and Mr Shorten's promise of $10 billion in funding for a Melbourne rail loop.
The survey has a margin of error of 2.3 per cent and was conducted by telephone with 46 per cent of the sample based on mobile phone calls.