Trump, a billionaire real estate developer, had the support of 15.8 percent of respondents in the online poll of self-identified Republicans compared to 16.1 percent for Bush, a former Florida governor.

They were followed by New Jersey Governor Chris Christie at 9.5 percent, Kentucky Senator Rand Paul at 8.1 percent, surgeon and author Ben Carson at 7.2 percent and Wisconsin Governor Scott Walker at 5.8 percent.

However, given a choice of three candidates – Bush, Trump or Florida Senator Marco Rubio – Bush had a comfortable lead at 42 percent among the respondents in the Reuters-Ipsos Republican poll, compared to 28.4 percent for Trump and 20 percent for Rubio.