New Zealand shares eked out another gain as the market digested the details of the governing deals made by the incoming Labour Government, with A2 Milk hitting a fresh record.

The S&P/NZX 50 Index edged up 0.55 points, or 0.007 per cent, to 8130.10. Within the index, 21 stocks rose, 21 fell and eight were unchanged. Turnover was $205 million.

Salt Funds Management's Matt Goodson said the market was focused on the new Government and figuring out the relative winners and losers from the policies announced as part of the deals Labour has made with New Zealand First and the Greens.

Retirement stocks are set to be one of the biggest losers and started to decline before the September election as Labour's polling improved.


Goodson said the stocks have been huge beneficiaries of rising house prices, and moves to lessen immigration and increase house building will change the backdrop for them.

Ryman Healthcare was the worst performer, down 3.7 per cent to $8.85. Metlifecare dropped 2.6 per cent to $5.73, and Summerset Group Holdings fell 2.2 per cent to $4.85. Arvida Group slipped 0.9 per cent to $1.17, while outside the benchmark index Oceania Healthcare dropped 3 per cent to 98c.

A2 Milk, which has booked strong gains this year as its sales in China continue to improve, was the best performer, up 3.6 per cent to $8.28.

"Particularly in the Australian market, there is a small number of stocks that attract momentum-type money," Goodson said, adding that the stock has benefited from the weaker kiwi dollar against the Australian dollar, along with other exporters.

A study from the University of Auckland's Liggins Institute, released over the weekend, showed A2 Milk can help with symptoms of lactose intolerance, although Goodson said the research was "more of a marketing angle until more information is available".

Freightways rose 2.6 per cent to $7.62, Z Energy gained 2 per cent to $7.14 and Property for Industry advanced 1.9 per cent to $1.63.

The Labour/NZ First coalition deal included plans for a full review of retail power pricing, although no further details have yet emerged. Goodson said the market was still trying to figure out what form the review would take.

"It's hard to say at this point exactly what this means, the impacts on the listed gentailers remains to be seen and it hasn't had a noticeable impact today," he said.

Genesis Energy, NZ's the biggest energy retailer, rose 0.8 per cent to $2.43, while Mercury NZ gained 0.4 per cent to $3.445. Meridian Energy fell 2.4 per cent to $2.82 and Contact Energy slipped 1.8 per cent to $5.55.

Fletcher Building shares are in a trading halt and were last at $7.96, having dropped 25 per cent this year.