The New Zealand sharemarket closed on a positive note today, with Freightways proving to be the biggest gainer of the day.

Shares in the express mail company pushed to a one-year high this morning, gaining 9c in early trading, after the company yesterday reported a strong second quarter growth.

Freightways later added a further 1c to close at 337.

The benchmark NZX-50 index closed up six points or 0.196 per cent to 3390.09 up from yesterday's close of 3384.38.

Sky City gained 3c to 330, Sky TV added 2c to 537, Telecom added 3c to 224 and New Zealand Oil and Gas gained 1c to 870.

Michael Hill gained 1c to 90c, The Warehouse slipped 1c to 354, and Kathmandu fell 3c to 213.

Infrastructure investment group Infratil added 2c, or just over 1 per cent, to 196, a day after Infratil Energy Australia disclosed the purchase of a generation site in New South Wales.

Melbourne-based OceanaGold shares added 33c to 375 after the company said today its proven and probable reserves in New Zealand had risen to 2.15 million ounces of gold at the end of December.

That was up from 1.92m ounces a year earlier, and after the company sold 268,000 ounces of gold from its New Zealand operations during 2010.

Stocks which slipped included fishing company Sanford, falling 8c, or 1.59 per cent, to 495, and Fletcher Building, which lost 2c to 821.

Contact Energy fell 2c to 622, Tower lost 1c to 198 and Air New Zealand remained unchanged at 139 after raising its international fares to cover rising jet fuel costs.

In the United States, the Dow Jones industrial average fell 0.04 per cent to 12,268.19, the Standard & Poor's 500 Index gained 0.2 per cent to 1332.32, and the Nasdaq Composite Index added 0.3 per cent to 2817.18.