The White House fence should be immediately raised by at least one metre to prevent people from breaking into the grounds, according to an independent security review.

A public summary of the panel's classified report also warned that the Secret Service - the US agency that guards the president - is "starved for leadership" and needs root and branch reform.

It called for an outside leader, better training and more staff to boost an agency that has grown "too insular."

Homeland Security Secretary Jeh Johnson set up the four-member panel in September after a mentally disturbed veteran scaled the fence and burst into the White House carrying a knife.

President Barack Obama and his family were not present at the time, but the incident was the latest in a string of security failures surrounding the US leader.

The panel suggested building a taller fence, saying that an extra four or five feet (1.2 to 1.5 metres) would make a difference, though it stopped short of detailing a specific design.

The White House, it suggested, should eliminate horizontal bars in the design or place them so that they provide little assistance to climbers, while curving the top of the fence outward.

"As the executive branch, Congress, and the service itself have all recognised, the fence must be addressed immediately," it said.

But the report also suggested that designers pay attention to the appearance of a building seen by hundreds of tourists every day.

"Importantly, designers of the new fence must balance security concerns with the long and storied tradition of the White House being the 'People's House,'" the report's summary said.

But the panel stressed that "the problems exposed by recent events go deeper than a new fence can fix."

"From agents to officers to supervisors, we heard a common desire: More resources would help, but what we really need is leadership," the summary said.

The last head of the Secret Service, Julia Pierson, resigned after the September fence-jumping incident, amid an outcry over several security lapses at the White House.

She had initially been appointed to clean up the service after a dozen agents were found to have hired prostitutes during a 2012 presidential trip to Colombia.

Obama then asked retired agent Joseph Clancy - a man in whose hands he placed his own life as head of the presidential detail - to steer his old agency through the immediate crisis.

But the panel warned that in the longer term, a leader from outside the agency would be better placed to clean house.