Cardiff owner Vincent Tan said Wigan are run by a "racist chairman" who had hired a "racist manager" as fallout from the appointment of Malky Mackay as team boss intensified Friday.
Malaysian businessman Tan was angered by Wigan chairman Dave Whelan`s comments about Jewish and Chinese people in a newspaper interview in which he defended his decision to hire Mackay.
Mackay was sacked as Cardiff manager by Tan.
Mackay was asked to fill the hot seat at Wigan, who like Cardiff play in England`s second-tier Championship, just three months after the governing Football Association revealed they were investigating text messages, sent during his spell in charge at Cardiff.
Mackay admitted the messages were "disrespectful" of other cultures.
"This is a racist chairman hiring a racist manager," Tan told the BBC.
"I hope that stops at two racists in Wigan, not snowballing to 2,000 or 20,000 racists in Wigan."
Whelan faced the prospect of an FA charge after he told the Guardian newspaper he did not find the word "chink", widely regarded as a derogatory reference to people of Chinese origin, offensive.
The word "chink" was reported to be in one of the Mackay text messages under investigation by the FA. There was also a phrase relating to Jewish football agent Phil Smith, which said: "Nothing like a Jew that sees money slipping through his fingers."
Whelan, 77, told the Guardian: "I think Jewish people do chase money more than everybody else."
Subsequently, Whelan apologised for any offence his comments might have caused but Tan said: "I think he insulted the dignity of all Jewish people. I think he insulted the dignity of Chinese."
The FA said Friday they would be investigating Whelan`s comments as a matter of "priority".
"We are very concerned to read about the comments that have been attributed to Dave Whelan," the FA said in a statement.
"As with all such cases, this will be dealt with as a priority ... the FA`s governance division have written to Mr Whelan. He has three working days to respond."
Mackay`s arrival at Championship strugglers Wigan prompted one of the club`s shirt sponsors to withdraw on Wednesday.
Earlier on Friday, Jewish Leadership Council chief executive Simon Johnson, a former FA and Premier League administrator, said: "Unfortunately these type of comments by Mr Whelan and Mr Mackay are using some of the worst old-fashioned, lazy and offensive racial stereotypes which have been used in the past as the basis for some quite vile anti-semitism."
However, Whelan received support from Hull manager Steve Bruce, who managed the Latics twice.
"Maybe sitting on the fence might be the easiest thing to do but I`ve worked under Dave Whelan twice -- I know him very, very well," said Bruce.
"There`s no racism in him at all. Sometimes words can be said which can be misplaced, they can be out there in the public domain, but certainly when I`ve worked with him there`s been no sign of racism," Bruce said.