It eventually spotted the men stuck on a mud bank near the airport about 1am and directed the hovercraft to their location.
It was unclear whether the jetski had run out of fuel or if it had run aground in the receding tide.
The men were both shivering cold but uninjured, while their jetski was found floating in the harbour this morning by a member of the public who notified police.
Westlake said the men's lack of preparation could have cost them their lives.
"You have to wonder why they didn't take cellphones or any other safety equipment. It can get very cold on the water, particularly if you're only wearing t-shirt and shorts.
"They can count themselves very lucky that they were spotted."