Global reinsurers are likely to pass on their mounting cost of the Canterbury earthquakes to their customers.

The kiwi fell below 80 US cents for the first time since January after weak US data and a surprise gain in local unemployment stoked bets the Reserve Bank may cut interest rates.

The kiwi fell to a three-month low after unemployment unexpectedly rose in the first three months of the year, raising the possibility of a Reserve Bank rate cut.