White men are becoming an "endangered species" in top business jobs as companies take on more women and ethnic minorities, Tesco's chairman has said.
John Allan told a retail conference "the pendulum has swung very significantly" - even though white men still dominate in UK boardrooms.
He said it was an "extremely propitious period" to be "female and from an ethnic background and preferably both".
Mr Allan later said his comments were intended to be "humorous".
In his speech, the day after International Women's Day, about the recruitment of prospective non-executive directors, Mr Allan said: "For a thousand years men have got most of these jobs, the pendulum has swung very significantly the other way now and will do for the foreseeable future I think.
"If you are a white male - tough - you are an endangered species and you are going to have to work twice as hard."
Mr Allan sits alongside eight other white men and three white women on Tesco's board.
Labour's Yvette Cooper, who chairs the Home Affairs Select Committee, reacted on Twitter.
Meanwhile, Sophie Walker, the leader of the Women's Equality party, joined calls for a boycott of Tesco saying, that Mr Allan was out of touch and his comments risk alienating customers.
She also highlighted data released by the Fawcett Society this week that suggested the pay gap was influenced by racial and gender inequalities, saying both groups were a "long way from endangering men's dominance of boardrooms".
Campaign group Women's March on London said Mr Allen's comments were "extraordinary" and the company should "step-up and show the world that diversity in leadership is no joke".
A spokeswoman said: "We call on the Tesco Board of Directors to commit to prioritise diversifying their board and provide a clear path with set targets on how they intend to do so.
"As consumers we are a powerful force and can exercise our freedom to shop elsewhere to support women and locally owned businesses. We encourage all of our marchers to do so until Tesco steps up."
But businesswoman Helena Morrissey, a campaigner for greater gender diversity in the boardroom, tweeted that media reports of Mr Allan's speech had put an "unfair spin on what he's trying to say".
Ms Morrissey's government-backed initiative, the 30% club, launched in 2010 with the goal of boosting female representation on FTSE 100 boards.
'A bit hyperbolic'
In a statement issued by Tesco to "clarify" his remarks to the Retail Week Live conference in London on Thursday, Mr Allan said: "The point I was seeking to make was that successful boards must be active in bringing together a diverse and representative set of people.
"There is still much more to be done but now is a good time for women to put themselves forward for NED roles.
"In all the organisations I have been involved in I have been a committed advocate of greater diversity and very much regret if my remarks have given the opposite impression."
Speaking to the Guardian newspaper, Mr Allan said: "The context was [that] I was talking to a bunch of aspiring non-executive directors, many of whom were women, and I wanted to give them some encouragement and, therefore, I used that rather colourful turn of speech.
"It was intended to be humorous, a bit hyperbolic.
"Clearly, white men are not literally an endangered species but I was actually wanting to make the reverse point, which is that it is a great time for women and people of ethnic minorities who want to get on in business."
A non-executive director sits on the board of a company but is not part of the executive team involved in day-to-day management.
According to analysis by headhunters Egon Zehnder, women held 26.3% of board positions in the UK's largest companies in 2016 - but it said recruitment, at 29%, was at its lowest proportion since 2012.
A report published in November said there was a disproportionately low level of diversity in the boardrooms of FTSE 100 companies.