California's governor approved a series of gun control measures Friday, including new restrictions on assault weapons, in the wake of recent mass shootings across the country that have triggered outrage.

Governor Jerry Brown signed into law six bills that were part of a package put before him by state lawmakers, further boosting firearms restrictions in one of the US states with the most stringent gun control laws.

"My goal in signing these bills is to enhance public safety by tightening our existing laws in a responsible and focused manner, while protecting the rights of law-abiding gun owners," Brown said in a statement.

The bills approved by the governor include a ban on assault weapons with magazines that can quickly be detached, new restrictions on loaning firearms and new punishment for falsely reporting guns as stolen.

One measure also requires an ID and background check for someone seeking to purchase ammunition.

The governor vetoed five other bills that had been approved by lawmakers, saying some were similar to an initiative that will be put to California voters during general elections in November and others did not add to existing legislation.

The package of bills -- denounced by gun-rights advocacy groups as "Gunpocalyse" -- was adopted on Thursday by state lawmakers who were spurred by recent mass shootings that have roiled the country, including the June 12 assault in Florida that killed 49 people and last year's terror attack in San Bernardino in which 14 people died.

Among the bills vetoed by the governor was one that would have required that stolen or lost guns be reported to authorities within five days and another limiting the purchase of a rifle or shotgun to one a month.

Democrats who control the legislature in California had voted in favour of the bills while most Republicans had voted against.

Gun control is a hot-button issue in the United States and Democratic lawmakers in Washington last month staged a sit-in in the lower house of congress to demand a vote on gun control legislation.

The protest came in the wake of the mass shooting in Orlando, the deadliest in modern US history.