The former US ambassador to the United Nations and South Carolina governor Nikki Haley told Republicans at a rally for Herschel Walker the Democrat in the Georgia US Senate race, the Rev Raphael Warnock, should be “deported”.

“I am the daughter of Indian immigrants,” Haley said in Hiram, Georgia, on Sunday. “They came here legally, they put in the time, they put in the price, they are offended by what’s happening on [the southern US] border.

“Legal immigrants are more patriotic than the leftists these days. They knew they worked to come into America, and they love America. They want the laws followed in America, so the only person we need to make sure we deport is Warnock.”

Haley is widely seen as a potential candidate for the Republican presidential nomination in 2024, a seemingly imminent declaration from Donald Trump notwithstanding. Her comment drew widespread criticism.

Cornell William Brooks, a Harvard professor and pastor, wrote: “Were it not for civil rights laws Black folks died for, Nikki Haley’s family might not be in America.

“Were it not for a HBCU [historically Black college and university] giving her father his first job in the US, Haley wouldn’t be in a position to insult Georgia’s first Black senator. Warnock’s history makes her story possible.”

Heath Mayo, an anti-Trump conservative, said: “Nikki Haley calling to deport Raphael Warnock perfectly captures how those that should’ve been serious and talented leaders were really just weak toadies ready to say anything for applause. This entire generation of GOP ‘leaders’ failed their test and let the country down.”

Walker and Warnock are locked in a tight race that could decide control of the Senate, currently split 50-50 and controlled by the vote of the vice-president, Kamala Harris. On Monday, the polling website FiveThirtyEight.com put Warnock one point ahead.

Haley also said Walker was “a good person who has been put through the ringer and has had everything but the kitchen sink thrown at him”.

Walker, a former college and NFL football star, has been shown to have made numerous false claims about his business career and personal life. Two women have said he pressured them to have abortions, allegations he denies while campaigning on a stringently anti-abortion platform.

Warnock, a pastor at a church once home to the civil rights leader Martin Luther King, won his Senate seat in January 2021, defeating the Republican Kelly Loeffler in a run-off. That victory and Jon Ossoff’s win over David Perdue for the other Georgia seat gave Democrats their precarious control of the chamber.