THE government’s harder stand on asylum seekers has the approval of most voters but has cost Labor supporters among its own base and enabled the Coalition to close the gap dramatically, the latest Herald/Nielsen poll shows.The poll also reveals a dramatic rise in voters concerned about immigration levels and population projections, with levels of concern higher than they were at the height of the Tampa crisis in 2001.The government’s decision 10 days ago to suspend for three and six months respectively the processing of Sri Lankans and Afghans who arrive by boat is backed by 58 per cent of voters.But Labor’s primary vote has fallen 3 percentage points in a month to 39 per cent.It all flowed to the Greens, whose support jumped from 9 per cent to 12 per cent. The Coalition’s primary vote was steady at 42 per cent, its first lead on primary votes since September 2008 when Malcolm Turnbull became leader.The loss of primary support left Labor clinging to the narrowest of leads on a two-party-preferred basis over the Coalition – 51 per cent to 49 per cent. The gap was last this narrow in June 2006.The Nielsen pollster John Stirton said it could be argued that ”the Rudd government’s new stance on asylum seekers has not won over one Coalition voter but has lost Labor votes to the Greens. There are other issues in play, of course, but it would appear that this is an important one for Green voters.”The poll coincides with the announcement yesterday that the mothballed Curtin detention centre near Derby, in remote Western Australia, will reopen to house those arrivals whose processing is suspended.This drew an angry response from the Greens and refugee groups, who said the government was embracing the ”desert detention mentality” of the Howard government.The Herald poll, taken from Thursday evening to Saturday night, sampled 1400 voters. It confirmed that immigration and population were hot issues.More than half, or 54 per cent, felt immigration levels were too high. This was an increase of 11 points since November. Also, 6 per cent felt levels were too low and 38 per cent felt they were about right, down from 43 per cent in November.Concern over immigration is much greater than in August and September of 2001 when the Howard government was milking the asylum seeker issue in the lead-up to that year’s election.Back then, 41 per cent felt immigration levels were too high, 10 per cent felt they were too low and 41 per cent felt they were about right.Now there is also concern about the Treasury estimate that the population, at present 22 million, will reach 36 million by 2050. Of those polled, 51 per cent felt it was too many people, 27 per cent said it was just right, and only 2 per cent felt it was too few.Since the release of the population projection, the opposition has been seeking to link illegal immigration with population growth.When the Treasury released its estimate, the Prime Minister, Kevin Rudd, initially embraced it, saying he welcomed a ”big Australia”. The government has since shunned the number as a target and appointed Tony Burke as the Population Minister to develop a strategy.