BEIJING (Reuters) - China's adoption agency said it was "very shocked and furious" about the findings in a Reuters report that exposed how U.S. parents use the Internet to abandon unwanted children they have adopted from abroad, including China.

A five-part Reuters investigation published this month found parents used message boards and forums on Yahoo and Facebook to send their unwanted children to virtual strangers with little or no government scrutiny, sometimes illegally.

"As to the report that refers to American families who are using the Internet to relocate children they have adopted and aren't willing to continue raising, we are very shocked and furious," the state-backed China Centre for Children's Welfare and Adoption said in a faxed statement to Reuters late on Tuesday. The centre was responding to a query from Reuters.

"This is an irresponsible act."

The Chinese adoption centre, commissioned by the government to govern overseas adoptions, said it "attaches great importance" to the Reuters report.

"As for the cases involving the adopted children from China, we are actively investigating and verifying and are awaiting a further understanding of the situation," the centre said.

The adoption agency said it is concerned about the lack of U.S. government regulation that was revealed in the series and will arrange to hold discussions with "relevant agencies" in the United States.

The adoption agency said it requires families who have adopted Chinese children to provide feedback six times in the first five years of adoption. It now plans to demand feedback until the child turns 18.

In the series called "The Child Exchange" Reuters analyzed 5,029 posts from a five-year period on a Yahoo message board. On average, a child was advertised on the site once a week in a practice called "re-homing". Most of the children ranged in age from 6 to 14 and had been adopted from countries such as Russia and China, Ethiopia and Ukraine.

(Read "The Child Exchange" series here http://www.reuters.com/investigates/adoption/#article/part1 )

(Reporting by Sui-Lee Wee and Hui Li; editing by Bill Tarrant and Ron Popeski)