Businessman and reality TV star Donald Trump has deleted a sexist joke about Democratic presidential candidate Hillary Clinton from his Twitter account, claiming the tweet was made by an unidentified staff member.

Trump, 68, is hoping to be nominated as the Republican candidate to run for president in the 2016 US elections, and on 2 April he formally registered his presidential exploratory committee.

The hard-talking real-estate mogul is well-known for posting comments on his Twitter account that are often quite incendiary and controversial, but his tweet on 16 April has crossed the line and offended many Twitter users.

The tweet in question is actually a retweet of a comment another user @mplefty67 made, which read: "If Hillary Clinton can't satisfy her husband what makes her think she can satisfy America?"

The comment references the Monica Lewinsky scandal in 1998 when international media discovered that Bill Clinton had had an affair with a White House intern.

Lewinsky became the butt of jokes for years and is only finally speaking out now about how the experience affected her life, while Hillary Clinton chose to stand by her husband and later became a senator and Secretary of State.

A spokesman for Trump told Raw Story: "It was retweeted by one of 10 staff members" who handle Trump's social media. "As soon as Mr Trump saw the tweet, he deleted it."

Trump has not apologised for the retweet or mentioned it since it was deleted. He has recently retweeted several tweets from fans/followers encouraging him to run for president, however, so the incident could be an innocent mistake.

Speaking at the First in the Nation Republican Leadership Summit on 18 April, Trump stressed that he wants to become president in order to make the US rich again – primarily by stopping China from influencing the US currency in order to bring more jobs back to the country, and not cutting social security.

He has said in interviews that he believes his children are old enough to take over the family business and that people who understand business and economics should be in the government as politicians "don't know what they are talking about".

Trump's TV show Celebrity Apprentice is one of the highest-rated reality shows on NBC and has been renewed for a 15th series.