

HOW big is too big? The former premier Bob Carr says Australia's population should be capped at 28 million. A federal Labor backbencher, Kelvin Thomson, says 26 million. The Stable Population Party of Australia says 23 million. The Greens want an inquiry to settle the matter. The Prime Minister, Kevin Rudd, says there is no ideal number, just what Treasury projects will happen: 35 million by 2050. ''That's what's happening,'' is Rudd's relaxed reply.

That is indeed what's happening, according to the latest population snapshot by the Bureau of Statistics. The population grew by a little over 450,000 people in the year to September. That is the equivalent of the entire population of the ACT and then some. About one-third of the increase came from natural factors: births minus deaths. The remaining two-thirds came from net overseas migration: arrivals minus departures.

Rudd has said he is a supporter of a big Australia, and the Herald, too, has warned against knee-jerk calls to cut migration at a time of skills shortages. But it is increasingly clear that our ability to sustain a larger population depends on the planning abilities of state and federal governments, and it is here that the Herald wavers.

The housing shortage is already approaching crisis levels. A lack of new supply is pushing the prices of existing homes beyond what young home buyers can afford. The public transport systems of our cities also need investment. The challenge of managing our scarce water supplies has never been greater. Given that most new arrivals to this country choose to settle in established cities, a bigger population will put an even greater strain on existing infrastructure.

Strong migration is one of the factors which helped Australia to avoid a technical recession last year. But what matters in the long term and what drives improvements in living standards is what we do with our existing population.