TRENTON, N.J. -- Before prosecutors described Rabbi Mendel Epstein as a leader in a devout Orthodox community, they played a short, grainy video clip that they say shows he is a criminal.

"Basically, what we're going to be doing is kidnapping a guy for a couple hours," he's heard telling two undercover FBI agents about what prosecutors say was a staged kidnapping in 2013.

Opening statements began Wednesday in the trial of Epstein and his three co-defendants: son David Epstein, Jay Goldstein and Binyamin Stimler. Mendel Epstein, who is accused of employing a kidnap team to force unwilling Jewish husbands to divorce their wives, faces charges of conspiracy to commit kidnapping and attempted kidnapping. The others face similar charges stemming from a staged kidnapping in 2013 and three other forced divorces.

Defence attorney Robert Stahl disputed the charges and portrayed Mendel Epstein, 69, as a "champion of women's rights."

"This is not a band of criminals extorting men for money or beating them for money," Stahl said, arguing that Jewish law allows recalcitrant husbands to be forced to giving a divorce document known as a "get."

He called the husbands the villains as Epstein, dressed in a dark suit, silently nodded toward Stahl.

Prosecutors allege the Orthodox rabbi's team used brutal methods and tools, including handcuffs and electric cattle prods, to torture the men into granting divorces. The kidnap team brought surgical blades, a screwdriver and rope to a staged kidnapping in 2013, authorities have said. Epstein allegedly told the undercover agents he arranged similar kidnappings every year or year and a half, U.S. Attorney Joseph Gribko said. Gribko noted the recordings throughout his opening statement, including Epstein allegedly describing how the cattle prods were used.

"If (the cattle prod) can get a bull that weighs 5 tons to move, you put it in certain parts of his body and in one minute the guy will know," prosecutors said Epstein told two undercover FBI agents posing as a brother and sister trying to force the sister's husband to grant the divorce. Gribko said he was recorded telling the agents the effort would cost $60,000.

Stahl, holding Epstein's 1989 book "A Woman's Guide to the Get Process," called Gribko's opening statement an "interesting and compelling story," but not evidence against Epstein.

Stahl argued that Epstein is simply good at advocating for women and that his reputation is "that he can convince these husbands to go give their wives a get." Stahl didn't dispute that "some laws may have been broken along the way," but said that did not include kidnapping.

Stahl, along with the other defence attorneys, sought to discredit David Wax, a witness in the case. Wax is co-operating with prosecutors after he pleaded guilty to conspiracy to commit kidnapping in a case where he was paid $100,000 to force a Jewish man to divorce his wife.

Prosecutors are expected to play footage on Thursday from recordings by undercover FBI agents.