New Zealand shares rose, led higher by Freightways and Comvita, as a2 Milk Co and Fletcher Building rebounded from recent selling ahead of the Christmas holiday.

The S&P/NZX 50 Index gained 57.05 points, or 0.7 per cent, to 8,401.2. Within the index, 34 stocks rose, 13 fell and three were unchanged. Turnover was $125 million.

"There's a strong Santa Clause rally that's ongoing and people looking to bed in the gains," said Shane Solly, director at Harbour Asset Management.

"It's a pretty positive run into the Christmas period, topping off what's been a positive year. At the start of the year, not many people would have expected a 22 per cent gain."

Freightways was the best performer, rising 3.5 per cent to $7.78, and Comvita rose 3 per cent to $8.24.

Summerset Group Holdings rose 2.1 per cent to $5.34. The Wellington-based retirement village developer and operator lifted full-year earnings guidance on strong resales volumes and margins as well as good margins on new occupation right sales.

It expects underlying profit to be in a range of $77m to $79m in calendar 2017, versus prior guidance of $72m to $75m, it said in a statement.

That represents an increase on the previous year's underlying profit of between 36 per cent and 40 per cent, it said.

"That's a pretty helpful upgrade, really highlighting that there is some resilience in the broader New Zealand economy," Solly said.

A2 Milk rose 2.3 per cent to $8.15.