New Zealand shares hit a fresh high led by positive earnings from Synlait Milk and Steel & Tube Holdings, while Auckland International Airport fell.

The S&P/NZX 50 Index rose 9.27 points, or 0.1 percent, to 7,363.1. Within the index, 28 stocks rose, 13 fell and 10 were unchanged. Turnover was $186.2 million.

A2 Milk Co led the index higher, up 4.4 percent to $2.12, after its supplier Synlait Milk said annual profit more than doubled to between $34 and $35 million on sales of higher-margin products. Synlait's shares, which aren't on the NZX 50, gained 7.8 percent to $3.73.

"Their gross profit per tonne jumped, there's solid demand for canned infant formula," Peter McIntyre, investment adviser at Craigs Investment Partners, said.


"That flows into A2 because A2 gets a lot of its powder from Synlait, the two are symbiotic in some respects. Remembering where Synlait's come from in the last year that's a solid result in a market that seems to be saturated with milk product."

Steel & Tube rose 4.3 percent to $2.19. The steel products manufacturer posted full-year earnings that beat guidance and lifted its dividends as the contribution from new acquisitions and cost savings helped offset weaker prices and margins, and costs related to "quality issues".

"They increased their dividend so that's a dividend yield of well over 10 percent, obviously that's an attractive yield in a low interest rate environment like we've seen today and I think that's where investors have flocked in to buy the stock," McIntyre said.

"There might be an argument they'd be better paying down debt - if you drill in, underlying cash flow improved slightly, it's a hard one to read but I think some punters are saying at the end of the day a strong dividend is good but you also need a strong balance sheet."

Metro Performance Glass gained 2.6 percent to $2. The company, which holds more than half of New Zealand's glass processing market, has made a move across the Tasman with the purchase of Australian Glass Group for A$43.1 million in a debt-funded acquisition that will immediately add to earnings.

Metro Glass posted its maiden profit as a listed company in May, benefiting from increased construction activity even as supply shortages meant some work was slow to start.

"The market may have thought Metro may try to bed down the NZ side of their business before they took off and made another investment outside of New Zealand," McIntyre said.

"They probably see this as an opportunity they can't miss and the market's tended to like it - it's on about a 5.4 ebitda (earnings before interest, tax, depreciation and amortisation) multiple which is pretty reasonable in this environment. The market's pricing more growth for Metro."

Auckland International Airport was the worst performer, down 1.7 percent to $7.06.

"It's back 2 percent for the week rolling in a market that's been driving to record highs on a daily basis," McIntyre said.

"A lot of brokers are concerned about possible regulatory threats, a lot of brokers have price targets well below where it's currently trading. A bit of money's been taken off the top and distributed amongst other stocks. It's widely owned by institutions and maybe they're taking some profit today."

Metlifecare advanced 2.5 percent to $5.80 and Summerset Group rose 2.1 percent to $4.96.

Vector gained 0.6 percent to $3.47. The Auckland-based electricity and gas distribution company has won for a second time against the Inland Revenue Department over its tax treatment for a $53 million payment made by grid operator Transpower.

Subject to any further appeal process by the commissioner, Vector will be entitled to a tax credit of $12.5 million plus use of money interest in relation to 2011 to 2015 years, it said.

Warehouse Group dropped 1.4 percent to $2.80 and Air New Zealand fell 1.4 percent to $2.20.