The club is close to Mr Key's heart. In 2012, he and his wife Bronagh attended a charity auction there, where two cups and a teapot from his infamous sit down with John Banks went under the hammer.
Bidding stalled at $1600 but eventually rocketed to $6300 after the PM offered to take the top bidder to a cafe for a cuppa.
Mr Key's office was unable to say whether he was booked in for a round in the near future, and he was too busy to comment on the vandalism.
Omaha Beach Golf Club manager John Phillis said staff and members alike were left devastated after discovering the damage.
"They've come in and done doughnuts and they've totally wrecked it. It's mindboggling and I'm just devastated.
"The passion that goes into a golf course is huge. Having it destroyed in a matter of seconds - it makes me feel sick."
Mr Phillis said the damage would cost between $40,000 to $80,000 to repair. Diggers would strip the grounds back to sand and if everything went well, it could be fixed within two months.
Mr Phillis said the club had received a lot of support over the last few days from other golf clubs and members alike. They were also looking at bumping up security at the site, such as installing cameras.
Michael Reid posted pictures of the torn-up golf course online this week, urging members of a Warkworth community group to "help in finding the culprits".
By last night, there were hundreds of comments in which the actions of those responsible were widely condemned.
"I would have thought there would have been lots of dirty tyre marks on the road. Be good to see their car get crushed in a crusher and them made to watch," Lorraine Mills commented.
Police said they were unaware of a complaint being made regarding the incident but Mr Reid understood the offender was driving a dark Mazda.
Mr Key's love of golf has been well documented, especially since he played a round with US president Barack Obama when the pair were in Hawaii last year.
Mr Key later told reporters he and the world's most powerful man had beaten his son Max Key and a presidential aide "handsomely".
His golfing handicap has steadily dropped since 2012, when it was a hefty 23.1.
By October last year Mr Key was playing off a much more respectable 11.9 and has teamed up with golfing prodigy Lydia Ko and legend Bob Charles in celebrity tournaments in the past.
