President Barack Obama says the United States has not overcome its history of racism following the arrest of a white man for the racially-motivated shooting deaths of nine black church members in South Carolina.

In an interview on Monday with comedian Marc Maron for his podcast show, Obama expressed frustration with the country’s rampant gun violence and long-standing racial tensions.

"Racism, we are not cured of it," Obama said. "And it's not just a matter of it not being polite to say nigger in public. That's not the measure of whether racism still exists or not. It's not just a matter of overt discrimination. Societies don't, overnight, completely erase everything that happened 200 to 300 years prior."

The president said the legacy of slavery in the US "casts a long shadow and that's still part of our DNA that's passed on."

Obama also condemned the powerful gun lobby in Washington for deterring US lawmakers from passing stricter gun laws, and said, "The grip of the NRA on Congress is extremely strong."

"I will tell you, right after Sandy Hook, Newtown, when 20 6-year-olds are gunned down, and Congress literally does nothing — yes, that's the closest I came to feeling disgusted," he said. "I was pretty disgusted."

Obama said America, where the right to own firearms is constitutionally protected, should learn a lesson from Australia, where firearms are strictly controlled and gun violence is almost unheard of.

Australians had a similar attitude toward firearms prior to a 1996 mass shooting that killed 35 people. Soon after, tight restrictions on gun ownership were imposed and no such incidents have been reported since.

Wednesday’s shooting at Emanuel African Methodist Episcopal Church has renewed perceptions around the world that Americans have too many guns and have yet to overcome racial tensions.

The white gunman, 21-year-old Dylann Roof, was arrested on Thursday, with media reporting that he had hoped his actions would incite a race war in the United States.

AHT/HRJ