Trading at about US82c overnight, the dollar has become a political issue in recent weeks, with calls from the Green Party among others for the Reserve Bank to intervene to bring it lower.

Meanwhile, opinions differ widely as to what direction the dollar is likely to head, particularly against the greenback, with forecasts for its value over the next year ranging from US65c to US90c.

It's perhaps not surprising, then, that many advisers choose not to currency hedge their clients' overseas investments; not only is it easy to get their picks wrong, their hedging can also contradict or even exacerbate the currency position of the funds their clients are invested in.

Norman Stacey of Diversified said his company used currency hedging, but only occasionally.

"Our default position is unhedged, unless we take a strong view one way or the other," Stacey said.

Changes in the relative value of the New Zealand dollar can have a big effect on returns, sometimes flattering and sometimes making performance look decidedly ugly, he said.

"Over a given period currency movements can overwhelm other movements in the portfolio."

Murray Weatherston of Financial Focus said, "A lot of people use the policy of least resistance; you hedge 50% so you're half right and half wrong.""

However, his view is not to try to hedge because in the context of longer term assets the currency will tend to "come out in the wash," he said.

Trying to pick currency movements can be risky for advisers, who don't "spend all day staring at screens" unlike currency traders, according to Weatherston.

"I don't know of anybody anywhere in the world who would claim to be accurate on currency forecasts over an extended period of time."