Rescue helicopter pilot John Funnell said weather conditions meant Mr Donaldson is currently braving gales, and is set to paddle into the path of a hail storm tomorrow morning.
Despite bad weather, Mr Funnell said Mr Donaldson was closing the gap, and was approximately 120 nautical miles away from the Taranaki coastline.
At this rate Mr Funnell expected Mr Donaldson to arrive on dry land early next week.
He said many people would be pleased to see him on dry land and his family were keen to get him back.
"He has been at sea for two months now, and has had a hell of a lot thrown at him, this is a feat I have trouble comprehending."
Mr Donaldson is aiming to raise awareness about increasing aerobic activity levels in our daily lives.
It is his second attempt at the crossing.