A mother and alleged pro-gun campaigner who was accidentally shot in the back by her four-year-old son could face criminal charges over the incident.

Jamie Gilt, 31, was hospitalised after her son apparently managed to pick up a gun and discharge it while she was driving, police in Florida have said.

Authorities have now recommended charging her with allowing a child access to a firearm, a crime which is punishable by up to 180 days in jail if convicted.

The state's child welfare agency is also investigating, according to a report on NBC news.

Ms Gilt is thought to have made numerous social media postings in support of gun rights, including one that said: "My right to protect my child with my gun trumps your fear of my gun."

Police said that she had placed a loaded handgun under the front seat of her pickup truck on the day of the shooting.

Her son, who had recently learned to unbuckle himself, managed to get out of his seat, pick up the weapon, and discharge it into his mother's seat - who did not initially realise what had happened.

"She felt something strike her in the back, then noticed the windshield of her truck was broken," said Putnam County Sheriff's Capt. Gator DeLoach.