Can someone ID this for me please?

Hi again,
my friend in NZ has a pond and this plant with pretty white flowers is growing in it. She can't find out what it is, so I told her I'd post it for her. Hopefully someone can ID it?
Thank you all again,
LeeAnne

The plant is the Water Hawthorn (Aponogeton distachyos)
http://davesgarden.com/pf/go/1300/index.html

thank you
I will get that info off to her ASAP.
LeeAnne

Hi,
After looking close at the pics, and she asked around locally as well, we believe it to be the Swamp Lily (Ottelia ovalifolia). The link you gave of the water hawthorn is close but the flower is different on hers. Thank you for the help. Greatly appreciated.
LeeAnne