HOLLYWOOD stars Jennifer Garner and Halle Berry have urged Californian legislators to back a bill aimed at limiting the ability of paparazzi to photograph children of celebrities, local media report.

The legislation, which specifically targets paparazzi and was introduced by a Democratic senator, would widen the legal definition of harassment to include taking pictures of or recording a child without the permission of a legal guardian.

"We're not just whiny celebrities ... We are moms here trying to protect our children," Berry, 47, testified on Tuesday. according to television station KTLA.

"I am asking you as a parent to pay attention," echoed Garner, 41, who has three children with actor Ben Affleck.

"Would you do anything differently for your child?"

US media and paparazzi say the legislation limits their right to information.

Berry, who is pregnant with her second child, has already testified in favour of the bill in June. At the time, she said her daughter was scared to go to school because of the paparazzi.

"Here come these men with cameras, besieging the school and these little children, all to get a photograph," she told lawmakers in Sacramento, the Californian capital.

"They cause chaos, they cause fear, the children and their parents are horrified, we start arguing, everybody's fighting, and the men seem to don't care at all."

The bill still has a ways to go before becoming law. If it makes it through the California legislature, it would head to the desk of Governor Jerry Brown who has the right to veto it.

Berry married French actor Olivier Martinez last month and the two are expecting their first child. Berry is also the mother of a five-year-old girl whose father is model Gabriel Aubry.