Home Secretary Theresa May told the BBC the NCA would be responsible for investigating organized, economic and cybercrime, border policing, and child protection.
The NCA is the third such policing body to be created in Britain, replacing the National Crime Squad set up 15 years ago and the Serious Organized Crime Agency, set up seven years ago, the BBC.
"Crime is falling in this country, but we can't be complacent. And particularly on organized crime, I don't think the last government put enough emphasis on this," May said.
Shadow Policing Minister David Hanson criticized the "government's hype" of the NCA.
"Most of the NCA is just the rebranding of existing organizations such as the Serious Organized Crime Agency, but with a substantial 20 percent cut imposed by the Home Office on their overall budget," he said.
"It is right to have stronger national action on organized crime with the NCA, on child exploitation and on intelligence -- but the government has to support this effort and not simply use this as a rebranding exercise to hide substantial policing cuts," he added.