US TV network Showtime and Sacha Baron Cohen have rejected allegations that the comedian duped guests on his new show by posing as a disabled veteran.

Showtime said in a statement on Monday that Baron Cohen “did not present himself as a disabled veteran” or wear any military apparel when he met Senator Bernie Sanders and former Republican vice presidential candidate Sarah Palin.

Last week, Ms Palin complained on Facebook that Baron Cohen “heavily disguised himself” as a disabled US veteran in a wheelchair when she was “duped” into an interview.

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Sarah Palin and Roy Moore have both said they duped by actor Sacha Baron Cohen for his new TV series, Who Is America? (AP)

She challenged Baron Cohen and Showtime to donate proceeds from the show to a veterans’ charity.

In his new show, Who Is America?, Baron Cohen dons various prosthetics and accents in an attempt to embarrass those on the right and left.

Defeated US Senate candidate Roy Moore is threatening a defamation lawsuit over a forthcoming episode.

He said he accepted an all-expenses-paid trip to Washington in February after being told he would receive an award for supporting Israel.

“I did not know Sacha Cohen or that a Showtime TV series was being planned to embarrass, humiliate, and mock not only Israel, but also religious conservatives such as Sarah Palin, Joe Walsh, and Dick Cheney,” he wrote on Facebook.

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Joe Arpaio said he is among the political figures who were pranked (Matt York/AP)

Former sheriff Joe Arpaio, who is running for the US Senate in Arizona, thought he was part of a show focusing on the top 20 most famous people in the United States.

The 86-year-old said he began to suspect something was amiss with the interview when Baron Cohen started using sexually explicit expressions.

He has not yet decided whether to take any action against Baron Cohen, who posed as a Finnish actor and wore a disguise during an October 2017 interview in Los Angeles.

“If they do a good job, maybe I’ll send them a thank you note,” Mr Arpaio said.