Trayvon Martin's killer George Zimmerman used money raised for his defence fund to pay off credit cards and other personal debts, recordings of prison conversations released by prosecutors Monday suggest.

Transcripts of the calls made by the accused murderer from Florida's Seminole County jail in April include instructions to his wife, Shellie, to "pay everything totally off", including credit cards from American Express and Sam's Club and some money owed to his mother.

The calls between Zimmerman, 28, and his 25-year-old wife also feature discussions over the amount raised on a website he set up shortly after his arrest for the February 26 shooting, in which he pledged that donations would be used "only for living expenses and legal defence".

Prosecutors last week charged Shellie Zimmerman with perjury for telling a judge that the couple was virtually penniless, despite having raised about $135,000 at the time. Judge Kenneth Lester also revoked Zimmerman's own $150,000 bail this month when he learned of the alleged deception.

The new details of the Zimmermans' financial affairs come in Monday's release by Florida state attorney Angela Corey's office of recordings of six jail phone calls made by the defendant between April 12 and 17.

They also include the revelation that Zimmerman feared for the couple's safety and asked his wife to buy them both bulletproof vests. "As uncomfortable as it is, I want you wearing one," he tells her.

Zimmerman, a neighbourhood watch captain, shot and killed Martin, an unarmed black teenager, during a confrontation at the gated Retreat at Twin Lakes community in Sanford, but he denies murder because he claims he acted in self-defence.

He was initially freed, but arrested and charged with second-degree murder on April 11 after Rick Scott, the Florida governor, appointed Corey to take another look at a case which sparked weeks of demonstrations and public outrage.

In one of the calls, on April 16, Zimmerman and his wife discuss changing passwords on his bank account, to allow her to access it, then he tells her: "When you get home, please pay off all the bills.

"You can go into mine [bank account] and make sure you pay the right American Express and everything.

"Pay everything totally off, the Sam's Club card, everything except for those two," referring to a car insurance bill and a water bill that could not be paid online.

In a call the following day, Shellie Zimmerman confirms she paid the credit cards. "I called all those companies to see the balances and I paid them all off," she said.

"I even paid, like, your mom, 'cause you knew you were paying her monthly. I, uh, I even paid my school."

Elsewhere in the conversations, the couple is heard making arrangements for regular transfers from Zimmerman's bank accounts into those of his wife and one set up by his sister Susie. Prosecutors say Shellie Zimmerman received $74,000 and his sister $47,000.

Zimmerman's lawyer, Mark O'Mara, has previously admitted that his client's failure to disclose the money to the court was "a mistake" which he said was made through "fear, mistrust and confusion".

O'Mara pointed out that the fund, which eventually raised more than $200,000, was closed down when he became Zimmerman's lawyer and that a new fund set up for legal bills and living expenses was independently managed.

Only six recordings of jail phone calls were released publicly on Monday because O'Mara has filed a motion to suppress 145 more.

"The calls are not only irrelevant to the charges against Mr Zimmerman, but they could jeopardise friends and family of Mr Zimmerman who are unrelated to the case," O'Mara said in a statement.

The recordings and transcripts are among a second round of discovery material that Lester ordered last week must be released by June 27. A spokeswoman for the state attorney's office said that the release of other documents, including statements given to police by Zimmerman on the night of the shooting, would not be affected by the defence motion.

O'Mara, meanwhile, will ask Lester for his client's release at a new bail hearing on June 29. If convicted, Zimmerman faces at least 25 years in prison, but no trial is expected before the middle of next year.