New Zealanders' real after tax average earnings have increased faster than those in Australia since 2008, Finance Minister Bill English said today.

"That's because Australia has had significantly higher inflation than New Zealand over this period, and tax cuts across the Tasman have been relatively modest compared to those in New Zealand," he told Parliament.

"As a result, the wage gap between the two countries has actually narrowed slightly.

"We are not getting too excited about that, because we are such a long way behind Australia to begin with. But it's a good start."

The figures use data on average weekly ordinary time earnings (per FTE) from Statistics New Zealand's Quarterly Employment Survey - the official series which is also used to calculate the wage floor for New Zealand Superannuation.

The figures have been adjusted to account for income tax and inflation - giving a true picture of changes in New Zealanders' spending power.

Since September 2008, real after-tax wages in New Zealand have increased by 8.7 per cent. Using a comparable series, Australia's real after-tax wages have increased by 4.8 per cent in the same period.

"By comparison, New Zealand wage growth significantly lagged Australia's in the nine years to September 2008. Over that entire period, New Zealand's real after tax wage growth was a paltry 3 per cent, compared with 19 per cent growth in Australia.

"Put another way, when Labour was in office, real after tax wages in Australia increased over six times faster than wages in New Zealand. No wonder the wage gap blew out under Labour's watch."