"Obviously the currency has had some pressure and a little of that has to do with the election poll results showing a very tight race," Williamson said.
"It's good for the exporters of this world, like Fisher & Paykel."
Williamson said the market may be quiet over the next few weeks ahead of the general election on September 23, with the most recent poll showing Labour ahead of National for the first time in 10 years, making investors uncertain about which way it will go.
"Investors on the buy side may be quieter, and even after the election we may not know what the result is for a while due to coalitions being formed," Williamson said.
A2 Milk Co was the best performer on the index, up 2.9 per cent to $5.71, with Fletcher Building gaining 2.6 per cent to $8.37 after a volatile week. Comvita rose 2 per cent to $7.55.
Auckland International Airport was the worst performer, dropping 1.8 per cent to $6.67, while Meridian Energy fell 1.7 per cent to $2.90 and Spark NZ dropped 1.7 per cent to $3.85.
Outside the benchmark index, Freightways dropped 1.7 per cent to $7.77. Dean Bracewell is to step down as managing director after 18 years in the role.
SeaDragon was unchanged at 0.6c. The company says it has an unresolved quality control issue which has hurt prices and is waiting to hear back from offshore customers who are assessing samples of its refined Omega-3 fish oil.
Intueri Education Group was unchanged at 1.1c. Liquidators have been appointed after ACG Education, the private equity-owned education services provider, bought its assets.