A nationwide Guardian-Lonergan poll identifies the almost 1 million people intending to switch their vote from Labor to the Coalition on 7 September as "Abbott agnostics" – more likely to be younger men who say they are choosing the "least bad" option.

The poll found the Coalition attracting 53.6% of the two-party preferred vote and Labor 46.4%, in line with aggregates of other nationwide polling.

But it also sought to identify some characteristics of the 950,000 or so people saying they intend to change their vote from Labor in 2010 to the Coalition in 2013.

The analysis shows that these vote changers are more likely to be male (56%) than the average Coalition voter (53%). They are also more likely to be aged 25-34 (31%) compared with the average Coalition voter (15%) and live in New South Wales (41%) than on average for the Coalition vote (34%).

Fitting the general perception of swinging voters as being politically disengaged, they are also more likely than the average Coalition voter to be disaffected with politics.

Of those who have shifted to the Coalition since 2010, 39% agree with the statement "I don't like any party. I am voting for the best of a bad lot", well above the level of agreement among all those who intend to vote for the Coalition (29%). Only 37% say they follow politics closely, compared with 44% of Labor voters and 46% of all Coalition voters. And 14% say they wouldn't vote at all if they didn't have to, compared with 11% of Labor voters and 7% of all Coalition voters.

But those sticking with the ALP are revealed to be in some respects even more disaffected than the election-deciding group who have shifted to the Coalition – with 49% saying they were voting for the best of a bad lot.

As Kevin Rudd prepares to defend Labor's record in government and present the ALP as the best party to protect Australian jobs at his campaign launch in Brisbane on Sunday, 5% of the electorate remains genuinely undecided.

With just a week until polling day, the undecideds appear evenly split as to who would make the better prime minister (Rudd 49%, Abbott 51%), lean towards the Coalition on economic management (55% trust the Coalition most to manage the economy, 45% the ALP). Some 71% of the undecided voters are women.

They are less negative about the performance of Labor than voters as a whole. Some 54% say it has been good and 46% poor, compared with 41% of all voters who say Labor has performed well and 59% who say it has performed poorly. And the undecideds are also politically disengaged. Only 11% follow politics closely, compared with the national average of 45%, and 83% agree with the statement: "I don't like any party. I am voting for the best of a bad lot."

Rudd is expected to use his campaign launch speech to remind voters of Labor's achievements in health, school funding, the national disability scheme and the national broadband network.

The Coalition enters the final week of the campaign without having released its policy costings, but promising no overall cuts to health or education.

The voice-automated survey of 828 voters on 29 August found Labor's primary vote on 35%, the Coalition's on 47% and the Greens' on 11%.