Illustration John Shakespeare There is a right-wing strand to this critique (see Abbott). And there is a political opportunist strand (see Abbott again). And there are environmentalists or conservationists who would be amenable to lowering the migration intake, which accounts for about half the overall rate of population growth, to reduce the strain on both the country's natural and man-made resources. The attractions of these positions are, in a sense, understandable. The state government is spending record amounts of money on transport infrastructure, while a record amount of new homes are being built in Sydney. Neither development seems to be touching the sides of the city's congestion woes, or reducing the pains of the housing market. Maybe there are just too many people around. "The key thing in all this should be the evidence, and not just opinions," says Glenn Withers, professor of economics in the Crawford School at Australian National University in Canberra. And on Withers' account – and on the account of many economists – one of the issues opponents of migration rates have to grapple with is that the evidence is that current levels contribute to the performance of the economy.

Former prime minister Tony Abbott. Credit:Getty Images "We know it has a substantial economic expansionary affect," says Withers. "We would not have weathered the GFC as well as we did without a strong expansionary migration program." But what about the strains on government resources caused by migration and population growth? Even then, the evidence suggests, migrants more than pay their way. "What is very clear from the evidence is that they contribute more to the public purse than they take out from the public purse," says Withers. One of the reasons is that migrants tend to be younger than the population as a whole. Governor of the Reserve Bank Philip Lowe before the House of Representatives' Standing Committee on Economics last week. Credit:Brook Mitchell When Abbott was prime minister, his government commissioned a Productivity Commission inquiry into the issue. That inquiry did find that high migration rates put pressure on housing costs (which, of course, benefits existing home owners).

But the inquiry also found that maintaining the migration intake helped the economy overall, and, importantly, per person. If the rate of net overseas migration was cut to zero, the modelling said, the cost to the economy would be about $7000 a year per person. "It's a legitimate question to ask whether immigration does any more than simply adding to demand," says the economist Saul Eslake. "And the answer according to these studies is that it does." More of us have better paid jobs because of the country's migration rate. Governments have more resources, in total, to cope with the pressures of population. Last week, a day after Abbott raised the idea of cutting immigration, the Liberal MP for the southern Sydney seat of Hughes, Craig Kelly, asked another economist if he thought the immigration rate should be tied to housing supply. The response, by the head of the Reserve Bank, Philip Lowe, was reasonably unequivocal for a person in his position. "Our immigration program I see as a source of national strength," said Lowe.

"To give that advantage up just so that we can take some pressure off housing prices, I find kind of problematic." Cutting the immigration program to reduce pressure on urban infrastructure like housing is the kind of simple solution that has complicated and negative ramifications. It would be better if governments faced up to the complicated solutions required to provide lasting responses to the issues facing places like Sydney. Here, Lowe also had a suggestion. The "best" housing affordability policy, the governor of the Reserve Bank said, would be investment in urban transport infrastructure. This investment would increase access to cheaper land, and provide the amenity needed as cities become more dense. The Abbott position is a cop-out. It would be absurd to undermine one of the best things about Australia because governments have failed to do their jobs well. This is particularly so when the federal government continues to promote tax incentives that skew the price of housing higher, and when its urban transport policy remains a puff of smoke. Jacob Saulwick is city editor.