New Zealand shares rose in light trading as earnings trickled off, with Auckland International Airport leading the index while A2 Milk Co continued to drop.

The S&P/NZX50 Index gained 20.69 points, or 0.3 per cent, to 7387.95. Within the index, 22 stocks rose, 20 fell and nine were unchanged. Turnover was $124.1 million.

Auckland International Airport led the index, up 2.9 per cent to $7.51. The airport announced its annual results on Monday, with net profit rising 17.4 per cent to $262.4 million while underlying profit rose 20.6 per cent to $212.7 million.

"That was a pretty strong result, it certainly beat our expectations and even though it trades at a lofty multiple it's a quality asset," said Peter McIntyre, investment adviser at Craigs Investment Partners. "I think a number of investors are wanting to buy the asset for the longer term and collect a dividend along the way."


Fisher & Paykel Healthcare gained 2.2 per cent to $9.88 and Genesis Energy rose 2.1 per cent to $2.22.

A2 Milk Co was the biggest decliner, down 4 per cent to $1.90. It's dropped 17.4 per cent since last Wednesday when it announced a return to full-year profit, meeting guidance, and a 127 per cent jump in revenue that was driven by infant formula sales in Australia and China.

In the US, progress is behind schedule, which A2 attributed to delays in achieving distribution with a number of larger retailers. US operations also had to cope with serious health issues for US chief executive Jeffrey O'Neill in the first half, who was replaced by Blake Waltrip, the company said.

"There's some concern over whether they can drive growth in the US market, which would be a catalyst for higher earnings, and maybe that's dampened down future earning expectations so people have taken some money off the table," McIntyre said.

Chorus fell 3.5 per cent to $4.39. The telecommunications network operator reported its annual earnings on Monday, saying profit was $91 million in the 12 months ended June 30, unchanged from a year earlier.

"There's further weakness, on light volume, but there are concerns about what's going to happen in 2020 now," McIntyre said. "There's a review on fibre pricing, and the share price had run particularly hard up into that result. It was within guided expectations but a number have awoken to the review on fibre pricing and how that would impact on Chorus, and markets don't like uncertainty, so you've seen some money taken off the top."

Z Energy fell 1.4 per cent to $8.51.

Outside the main index, Tenon gained 7.1 per cent to $2.70. The Taupo-based wood processor's US operations are under offer from a New York-based private equity firm for US$110 million that the company's directors say will allow a substantial capital return to shareholders, despite a $31 million writedown in the carrying value of the assets to be sold.

Energy explorer New Zealand Oil & Gas rose 6 per cent to 53c. The company will make a tender offer to shareholders to accelerate the buyback of up to 40 million shares.

Pyne Gould Corp was unchanged at 22c. The investment group has avoided being suspended from the NZX after filing its annual results a day late, revealing a drop in income and a narrower full-year loss.

Veritas Investments was unchanged at 47c. The owner of the Mad Butcher franchise and Nosh food market outlets is in talks with its bank over the terms of its debt but believes it can continue as a going concern.