NEW DELHI (Reuters) - India is investigating Wal-Mart Stores Inc. <WMT.N> over allegations it violated the country's foreign exchange rules, a senior law enforcement official with knowledge of the matter, told Reuters on Friday.

An Indian lawmaker has accused Wal-Mart of "clandestinely and illegally" investing $100 million in the multi-brand retail business of its wholesale joint venture partner, Bharti Enterprises, as early as 2010, before India allowed foreign companies to operate front-end stores.

"Yes, the Enforcement Directorate has initiated an investigation into the allegations against Wal-Mart," said the official, who declined to be named.

Wal-Mart has denied the allegations since they first surfaced last month and said it is in compliance with Indian laws.

(Reporting by Satarupa Bhattacharjya, writing by Rajesh Kumar Singh, editing by Ross Colvin)