Despite all the headlines, it's not the boat people we need to worry about – it's the other 2.3 million arriving tomorrow just when public investment in the nation is at an all-time low. That's the investment necessary to accommodate the increased population and maintain our quality of life. Or not.

OK, it's a slight exaggeration to say they're turning up tomorrow, but it's a bit like that from a historical perspective. And it may as well be tomorrow as far as our public preparedness goes. The nation's infrastructure, especially public transport, is groaning under its present load yet we're adding 2.3 million over the next five years, roughly 40 per cent by birth, 60 per cent by immigration. (The actual new arrivals figure is bigger than that – this is the net population growth after some of us shuffle off.)

That's far from a shocking discovery, but the reality of our population base and growth rate has crept up on us. It's just mathematics that a population of 23 million growing at our present rate of 1.8 per cent means about 10 per cent more people in five years – 2.3 million.

Phrased like that though, it was one of the insights within a speech by the Reserve Bank deputy governor, Philip Lowe, last week. Lowe cited this population growth as one of the reasons to be optimistic about business investment picking up. The dollar is weaker, business confidence has improved, as has the outlook for our key trading partners and interest rates are low.