New Zealand shares fell on Thursday in the busiest session so far this year, amid concern the earnings season may not reveal results that warrant high stock valuations.

The NZX 50 Index fell 16.706 points, or 0.4 per cent, to 4195.24. Within the index, 26 stocks fell, 12 rose and 12 were unchanged.

Turnover was $202.7 million, almost twice the daily average.

Telecom fell two per cent to $2.305 with 11.4 million shares changing hands.

Fletcher Building, the biggest company on the index, fell 0.8 per cent to $8.90, with 7.4 million shares traded.

Sky Network Television ended the day unchanged at $5.17 with 4.4 million shares changing hands.

"On one side there's a question mark about some of the earnings," said David Price, a broker at Forsyth Barr.

"We've had quite a strong run and (price-earnings) multiples are above 15" for the NZX 50.

"If the earnings are there, that's fine," he said.

Pumpkin Patch, the children's clothing chain, fell 2.9 per cent to $1.33, the biggest decline on the NZX 50.