The wage gap with Australia is around 40 per cent and it's going to get bigger, ACT leader Don Brash says.
Dr Brash was chairman of the 2025 Taskforce, set up in 2009 to find ways to close the gap, and he says when it started work the difference was about 35 per cent.
"In the 10 years to 2008, 280,000 Kiwis have left for Australia," he said in a speech to the Northern Club in Auckland on Thursday.
"The taskforce projected that on current trends we will lose another412,000 between now and 2025 - that's a serious threat to the existence of the kind of society most of us were brought up in and the kind of society most of us want."
The government rejected the taskforce's recommendations for closing the gap, saying they were too radical, and wound it up before it issued a second report.
Dr Brash says Treasury projections that New Zealand's economy will grow by 2.4 per cent a year have to be compared with an assumed growth in Australia of 3.2 per cent.
"The bad news in that is the gap between our incomes and those in Australia is likely to continue to get wider," he said.
Dr Brash, a former Reserve Bank governor and a former leader of the National Party, delivered scathing criticism of the way the government is handling the economy.
He says the balance of payments deficit is going to get worse, and the government has done nothing to reverse the "dopey" policies of the previous Labour government.
He also says the government borrowed about $20 billion to stay afloat during the last financial year and it's still racking up debt.
NZN