Lawyers for the accused murderer George Zimmerman released a series of texts and photographs from Trayvon Martin's cellphone on Thursday, showing the Florida teenager discussing guns, fighting and smoking marijuana.

The move appears to be at attempt to discredit the 17-year-old's character ahead of Zimmerman's trial for second-degree murder next month, at which the neighbourhood watch leader's defence team will claim Martin was the aggressor in their fatal confrontation in a Sanford gated community in February 2012.

Mark O'Mara, Zimmerman's lead attorney, still has to convince circuit court judge Debra S Nelson to allow the evidence to be shown to jurors, against the objections of prosecutors who insist the teenager's history is irrelevant to the case.

But the release of more than 20 pages of records from the phone, together with the photographs and several videos, are a clear indication of the defence strategy for the trial scheduled to begin on 10 June, with Zimmerman, 29, denying murder on the grounds of self-defence and facing at least 25 years in jail if he is convicted.

In the text messages released on Thursday, Martin tells a friend that his mother had kicked him out of her house because he had been suspended for skipping school, and told him that he needed to move in with his father.

In others, he talks about using marijuana. "Oh, u smoke?" a friend asked him. Martin replied: "Yea do u??"

A third topic of conversation is organised fighting. One message to a friend refers to an apparent contest with another youth late in 2011, with Martin writing: "he got mo hits cause in da 1st round he had me on da ground an I couldn't do ntn."

O'Mara has insisted it was Martin who attacked Zimmerman, breaking his nose and smashing his head on a concrete pavement during a fight before his client managed to free his gun and fire off a single, fatal shot to the teenager's torso.

The transcripts of the text messages released on Thursday are blacked out in many places, making it unclear who Martin was talking to in his various discussions. But several are to the so-called Witness 8, a girlfriend who has also claimed she was on the phone to him as he walked through the Retreat at Twin Lakes community and encountered Zimmerman on February 26 last year. "U gotta gun?" he asked her.

Two other messages appear to confirm his interest in weapons. Eight days before his death, a friend texted him: "You want a .22 revolver". No reply is shown.

Days later, he asks another unidentified friend: "U wanna share a .380".

Among the photographs recovered from the phone are several that have already been circulated online but which are appearing in formal court submissions for the first time.

One is a close-up of a handgun, believed to be a .40 calibre Smith & Wesson. Others show Martin blowing smoke from his mouth, and there are two pictures of what appear to be cannabis plants.

State attorney Bernie de la Rionda has already asked Judge Nelson to ban evidence of Martin's marijuana use at the trial but defence lawyer Don West said it was relevant because Zimmerman said in his 911 call to police before the incident that he was following a suspect who "looks like he is up to no good or he is on drugs or something."

West has argued that the autopsy report should be presented to jurors.

Judge Nelson is expected to rule on that and several other pre-trial issues at a one-day hearing in Sanford on Tuesday. The trial could last up to six weeks.