A US woman has been arrested for allegedly hiring an undercover police officer to kill her husband of six months, authorities said.

Dalia Dippolito, 26, of South Florida, was charged with solicitation to commit first-degree murder, a police spokeswoman said.

Dippolito gave an informant pictures of her husband, 38-year-old Michael Dippolito, and $US1200 for a hit man to purchase a handgun, according to a probable cause affidavit.

She also offered to create an alibi for herself and detailed her husband's daily schedule.

Police allege that an undercover officer posing as a hit man called Dippolito on Monday afternoon and arranged a meeting.

The officer asked for $US3000 in cash and a key to the couple's home.

The undercover officer later met Dippolito in a pharmacy parking lot and asked if she was sure she wanted her husband killed.

She laughed, according to the according to the affidavit, and said: "I will be very happy."

Dippolito discussed getaway routes, her home's security system, the location of her husband on Wednesday and the fee for the task, and the officer again asked if the woman was sure.

"I'm not going to change my mind," she responded, according to the documents. "I am 5000 percent sure I want it done. When I set my mind to something, I get it done."

Authorities staged an elaborate crime scene outside the Dippolito home on Wednesday morning, complete with yellow crime tape and several police vehicles.

"The bottom line is, we wanted her to believe without question that when she arrived that her husband was dead," Slater said.

Officers then contacted Dippolito at her gym and told her to come to the house.

When an officer told Dippolito that her husband was dead, she broke down in tears, a video of the operation shows.

Dippolito was then taken to the Boynton Beach Police Department, where she was told of the investigation and arrested.

Michael Dippolito, who was informed of the case Wednesday morning, was also at the police department, as was the undercover officer who Dalia Dippolito believed was going to kill her husband, according to a police news release.

A call to a telephone number listed for Michael Dippolito connected with a signal that sounded like a fax machine.

A call to a cell phone number for Dalia Dippolito was unanswered and a message was not immediately returned.

"It seems like it just hasn't hit him yet," Slater said of Michael Dippolito. "But the more he thinks about it, the more things that have happened over the past couple months are starting to make sense to him."

AP