The 'It's Chico Time' singer, 47, was said to have been undergoing further tests after falling ill on the way back from a gig last weekend.
A statement from his publicist Kym Rowlingson said: "We can confirm that Chico has sadly suffered a stroke.
"This has been a great shock to Chico, his wife and their two children, also his close friends and family.
"We thank you in advance for giving Chico and the family some privacy at this time.
"Chico is now undergoing further tests."
He had teamed up with fitness fanatic Elishah Crutchley to open The Workout, in New Street, Wellington last year.
He officially opened the studio, holding a master class for selected guests on its first day.
As well as reaching the quarter-finals of the 2005 series of The X Factor with his memorable performances, Chico Slimani later took part in Dancing On Ice.
His spokeswoman said that further statements will be released later.