The New Zealand dollar weakened as investors favour safe haven assets as concern rose about the future of cash-strapped Greece after Eurozone leaders stepped up their demands for reforms at meetings over the weekend.
The kiwi dropped to 67.01 US cents at 8am in Wellington, from 67.22 cents at the New York close and 67.61 cents at 5pm on Friday.
The trade-weighted index fell to 70.87 from 71.29 on Friday.
Investors are feeling less confident that a deal between Greece and its creditors will be reached after no agreement was secured at weekend meetings.
Eurozone leaders told Greek officials at an emergency summit on Sunday that it must enact key tax, pension and privatisation reforms by Wednesday before they will restart talks.