UPDATE 1-Kazakhstan says AES underinvested in power plants

* Government says AES failed to invest $460 million

* AES denies allegations

ASTANA, April 30 (Reuters) - Kazakhstan on Friday accused U.S. company AES (AES.N) of failing to invest $460 million into its power plants in the central Asian country as required by contract, a charge the company has denied.

"AES has failed to meet investment pledges worth $459.5 million," a spokeswoman for the Kazakh anti-monopoly agency said, adding a finance ministry working group was considering reviewing a contract with AES.

She declined to explain what contract could be reviewed.

A spokesman for AES, which operates four power plants in Kazakhstan and manages two state-owned power distribution companies, denied the allegations.

"AES is meeting its investment pledges and does not plan to stop investing in Kazakhstan," Alexei Bendz said.

AES has been working in Kazakhstan since 1996 and its plants supply consumers in Kazakhstan and neighbouring Russia. (Reporting by Rausan Nurshayeva and Olga Orininskaya; Writing by Olzhas Auyezov; Editing by Dan Lalor)