WELLINGTON, Dec. 13 (Xinhua) -- The New Zealand economy will continue its momentum over the next few years, underpinned by investment, productivity and wage growth, Finance Minister Grant Robertson said on Thursday.

The Treasury's Half Year Economic and Fiscal Update (HYEFU) showed that the economy is healthy and the government is managing the books carefully in accordance with the Budget Responsibility Rules, Robertson said in a statement.

"This is important given the warnings of growing risks around the volatility of the international growth outlook, which could feed through to the New Zealand economy," Robertson said.

Thursday's forecasts showed the government's plan to help transit New Zealand economy to more productive, sustainable and inclusive growth is working, Robertson said.

The forecasts showed positive labor productivity growth after five years of negative growth; wages to increase by over 3.3 percent per year; business and residential investment growth around 4 percent per year; export growth around 3 percent per year, with the terms-of-trade remaining strong; and unemployment to stay low around 4 percent as businesses continue to hire.

These factors will drive GDP growth of about 3 percent per year over the next couple of years, according to the HYEFU forecasts.

Robertson said that this represents strong growth at a time when the economy is running at capacity, and is in line with other forecasters.