US president Barack Obama says he will ban the use of some military-style equipment by police departments.

For more than a decade the Pentagon has given surplus military equipment to law enforcement bodies.

But the president's taskforce on 21st-century policing has recommended that tracked armoured vehicles, bayonets, grenade launchers and ammunition of .50-calibre or higher should no longer be shared.

"We've seen how militarised gear can sometimes give people the feeling like there's an occupying force as opposed to a force that's part of the community that's protecting them and serving them," Mr Obama said.

"It can alienate and intimidate local residents and sends the wrong message, so we're going to prohibit some equipment made for the battlefield that's not appropriate for a local police department."

The move comes after unrest in US cities over the deaths of black men at the hands of police officers, many of whom where heavily armed with military-grade equipment.

While the use of explosive-resistant vehicles with tracked wheels like those seen on army tanks will be banned, police departments will have to provide added justification for the use of other equipment such as mine-resistant ambush protected (MRAP) vehicles and riot shields.

Mr Obama announced the steps, which are the result of an executive order, during a visit to Camden, New Jersey, where he pushed efforts to encourage trust-building between police and the communities they serve.

The fatal shooting of unarmed teenager Michael Brown by a Ferguson, Missouri police officer last August was followed by a string of highly publicised fatal encounters between police and black men.

Last month, Walter Scott was shot by an officer while fleeing the scene of a traffic stop in North Charleston, South Carolina, while violent protests erupted in Baltimore after 25-year-old Freddie Gray died after sustaining spinal injuries while in police custody.

Protesters in Ferguson felt the methods police used to prevent the demonstrations from turning violent were excessive, and the US justice department has since launched a review of St Louis County law enforcement's response to the unrest.

The turmoil in Ferguson and Baltimore also highlighted divisions between black and white Americans.

In the aftermath of the Baltimore riots, Mr Obama has been speaking out more about race, with a speech in the Bronx on increasing opportunity for young minority men and during a panel discussion on poverty in Washington.

Mr Obama's remarks in Camden were the fourth time in as many weeks that he has held an event to discuss his ideas for improving life for poor black communities.

Demonstrators across the US blame the police's increasing use of military equipment for the excessive force deployed against anti-discrimination protesters. ( Reuters: Brendan McDermid )

ABC/Reuters