Sydney suffered its ninth drive-by shooting in eight days when four shots were fired at a house in western Sydney in the early hours of Tuesday.
Mr O'Farrell said he asked police at a meeting on Monday if gun laws should be tightened.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
"They didn't at this stage indicate they thought that was necessary," he told reporters in southwest Sydney.
"We do of course have national gun laws, because that recognises that if one state goes it alone, too often they can be circumvented by things coming across the border.
"What we do see, regrettably, is too many people with access to guns, often stolen."
Mr O'Farrell said it was also a national issues for the federal government.
"There are too many guns out there. They are accessed by the criminal underclass, so there are concerns that I have about the way in which guns not only come into this state but also into this country," he said.
"I have had discussions and I will continue to have discussions with the federal government about how we can ensure the national gun laws are working effectively."
A woman and her two children, aged three and six, were asleep when the shots hit the home on Coleridge Road, Wetherill Park, about 1am (AEDT) on Tuesday.
Police have ruled out any link to other recent drive-by shootings, which have been blamed on a turf war between rival organised crime gangs.
Mr O'Farrell was confident police would catch those responsible for the shootings, particularly now the resources of the powerful NSW Crime Commission were available.
"No one expects there to be overnight success with this, but police are doing the job," he said.
"The Crime Commission with all of its powers has now been put onto the task, and I'm confident that police will get the results that the public so desperately wants."
NSW Police Minister Mike Gallacher on Monday announced police would have access to the coercive powers of the commission, which can compel witnesses to give evidence.
It is hoped this will break down the wall of silence that has so far hamstrung investigations.
