Joost wants to play for us after the 2003 World Cup. To be honest, he's the LAST player we want.
Chief executive Keith Grainger could not hold back his anger for van der Westhuizen, saying: "He has not had the courtesy to even contact the club himself. He's left it all to his agent."
The Springbok star scrum-half has snubbed the club, opting to sign a new contract with the South Africa Rugby Union and thereby binning a contract he had already signed to play with the Rodney Parade outfit this season.
His actions have left Newport supporters with a feeling of huge disappointment and Newport officials seething.
Grainger revealed that the club were acting quickly to capture another star name before the Heineken European Cup registration deadline on Friday.
But regarding Van der Westhuizen he said: "There is a key word here and rugby players and their teams must have it.
That word is integrity and it seems to be hard to find in this man.
"On Monday afternoon he was still saying he was coming and had a flight booked.
But he didn't get on it and left it to his agent to cancel the booking.
"If he's saying now that coming here could have affected his international rugby, then he should not have signed in May. He knew that then.
"He owes not only the people of Newport but probably all rugby players a public apology. He's not done his colleagues any favours because it could set a precedent."
Van der Westhuizen had signed a one-year contract with Newport.
"Everyone understands why he's done what he's done but the point is that he knew that when he signed the contract in May.
"I have no problem with him playing in the World Cup - but he could have done that with us!"
That issue concerns the release of the now Newport Enemy No1 to play international rugby for his country.
But Grainger said that was no problem with Newport as they already do that for current stars like Fijian lock and Black and Ambers captain Simon Raiwalui.
Grainger admitted the club were looking for another star name, but said: "We don't want to make any comment or fuel speculation about it because the fans have been let down once, but clearly we are after an international player."
Although Grainger would not say who the Black and Ambers were chasing, they have been linked with van der Westhuizen's Springbok number two Dan van Zyl, of Western Stormers, and possibly a top New Zealander.
In South Africa, as in some other nations around the globe, players have contracts not just with their clubs but with their unions. That is the case with SARFU and their internationals.
But, said Grainger: "Others like Samoans and Tongans are making nice little livings around the world because they are not contracted to their union.
"This guy has let us down and a loyal team member wouldn't have done that, " he added.
NO SHOW: Joost van der Westhuizen has been slammed by Newport officials for turning his back on the club