Voters in Anthony Albanese's Sydney seat desert the minor party as support in even inner-city strongholds falls away

The Greens are losing support even in their inner-city strongholds, with a Guardian Lonergan poll in the Sydney seat of Grayndler dashing the minor party's hopes that voters would switch in protest at the big parties' hardline asylum policies.

The poll, taken on Thursday night, shows the Greens candidate Hall Greenland on just 22% of the primary vote, losing 4 percentage points compared with the 2010 result, when the Greens came in second and reduced deputy prime minister Anthony Albanese's margin to 4.2%.

The poll of 966 voters shows Greenland coming third, well behind the Liberal Cedric Spencer on 28% and Albanese on 47%.

That result would make it immaterial whether the Liberals carry through with what the Greens leader, Senator Christine Milne, described as a "cruel" threat to preference the Greens last, because Greens preferences would be distributed rather than Liberal preferences. Based on the poll results, that would take Albanese to an overwhelming victory, with 66% of the two-party preferred vote.

After the retirement of founding leader Bob Brown and concerted attacks by both major parties, the Greens have been attracting only 9% support in nationwide polls.

That is well down on a record 13% of the vote in 2010, when the party's first lower house MP Adam Bandt won the seat of Melbourne and its Senate representation rose to nine.

A recent Galaxy poll in Melbourne, which showed Bandt on a huge 48% of the primary vote, had raised the party's hopes that Labor's move to the right on issues such as asylum was boosting support for the Greens in similar inner-city seats.

The Guardian Lonergan poll in Grayndler, and a ReachTel poll in Melbourne which showed lower support for Bandt, suggest the Greens may be the biggest losers from the polarisation of Australian politics after the tumultuous hung parliament and the presidential-style focus on the big parties' leaders during the campaign.

Voters in Grayndler, like most around the country, say the economy and leadership will be the biggest factors in their choice on 7 September.

Of those polled 28% said the economy was the most important issue to them, 28% nominated leadership, 20% education, 14% asylum and 10% the carbon tax.

Men were more likely than women to be most influenced by the economy and leadership and women more likely than men to be influenced by education.

In a campaign in which both Labor's Kevin Rudd and the Coalition's Tony Abbott are now trying to present their messages as "positive", 49% of Grayndler voters thought Rudd had the most "positive" pitch, 27% nominated Abbott and only 24% Milne.

And a massive 57% of those polled said they most trusted Labor to manage the economy, with 35% saying they trusted the Liberals and only 8% trusting the Greens.

But the poll suggests Albanese might have had an even more decisive victory under former prime minister Julia Gillard.

The return of Rudd as the leader of the Labor party has had a slightly negative impact on ALP voting intention in the electorate. More than three in 10 (31%) said they were less likely to vote for the party as a result of the leadership change, while 26% said the return of Rudd made them more likely to vote Labor.

Milne has been appealing to voters to support the Greens as the only alternative to the main parties, saying they have similar policies on refugees and on environmental issues such as mining in Tasmania's Tarkine, and have refused to raise the level of unemployment benefit and the single parents payment. She said the move by the Liberals to preference the Greens last was aimed at squeezing out the minor party.

The Greens are defending Senate seats in Tasmania, South Australia and Western Australia and are concerned about the prospects of their South Australian senator, Sarah Hanson-Young.

Just 6% of those intending to vote for Albanese said asylum issues were most important for them, compared with 34% of those who intended to vote for Greenland.

The poll, by Lonergan Research, used voice-automated telephone interviewing.

Correction, 10 August 2013: The original version of this article said Hal Greenland had come second in Grayndler in 2010. In fact another Greens candidate ran for the seat in 2010. This has been corrected.