Wishart, 31, recently turned down one of the new - and contentious - contracts offered by Zimbabwe Cricket and this is thought to have prompted his decision. He said that "stress from the problems in local cricket" was behind his announcement.
Wishart played 27 Tests and 23 ODIs for Zimbabwe, averaging 22.40 and 23.22. His unbeaten 172 against Namibia in Harare was the highest individual score in the 2003 World Cup.
"It's a hard decision, but I can safely confirm that I have retired from all forms of cricket." Wishart said. "Yes, I was offered a contract but I was not happy with it, and to be honest, I was just tired of Zimbabwe cricket, the fighting, and everything.
"I think we are under a lot of pressure. If we do not sort out things now we might destroy everything that we have built and there will be no cricket for youngsters in the future for coming through the system."
Trevor Gripper, one of the senior Zimbabwe players now on the sidelines of international cricket, said he will be playing club cricket but added he did not believe he will ever be selected for Zimbabwe again despite insistence by the board that non-contracted players can be picked. Gripper plays for national league side Old Georgians Sports Club in Harare. Zimbabwe's provincial club cricket begins on Sunday.
"I will play for my club when work allows", said Gripper, who has just retuned from a honeymoon after his marriage last month. "But on the national team, we have to stop dreaming. These guys have never done what they say they will do. We are told that if you score runs and take wickets you'll get selected, but I doubt if that is going to happen.
"I am happy to play club cricket, and I'm willing to offer my advice if anyone wants it, and help out the youngsters at the club. But the reality of the situation is that club cricket is in a terrible state. First-class is a joke. Standards have gone down. Honestly, where in Zimbabwe can we get players for five first-class sides? If we can't do that then that won't be first-class cricket."
ZC have added a fifth first-class side in Masvingo province, but in a plan to incorporate the province into Zimbabwe's first-class competition, the Logan Cup, has not yet been announced.
The statements by Wishart and Gripper further undermine attempts by the Zimbabwe board to show the world that the situation in the country is on the mend. Earlier in the month, the national players issued a statement condemning the behaviour of the board, and immediately after the board's AGM was held in near farcical conditions with journalists barred and stakeholders prevented from quizzing senior officials.