MUMBAI (Reuters) - The Indian joint venture of Wal-Mart Stores Inc has suspended its chief financial officer and other employees as it investigates alleged violations of U.S. anti-bribery laws, a development that could hamper India's efforts to open its domestic supermarket sector to foreign investment.

Wal-Mart, the world's largest retailer, said last week it has opened internal inquiries or investigations into bribery allegations in Brazil, China and India, which follows an earlier probe in Mexico.

"The suspension is a routine global practice followed in such investigations," an official at the Indian unit said, declining to be named. "We cannot carry out a fair investigation when the people we are investigating are in office. What we must not forget is they are innocent until proven guilty," the person said.

Separately, a spokeswoman for the joint venture confirmed the suspensions and said the venture was "committed to conducting a complete and thorough investigation." Wal-Mart's partner in the venture is Bharti Enterprises.

Indian authorities are also investigating claims that Wal-Mart violated foreign exchange rules when it invested $100 million in a domestic unit owned by its wholesale joint-venture partner.

Indian opposition parties and allies within the Congress party-led coalition government in New Delhi are opposed to allowing global giants like Wal-Mart into the retail sector, saying to do so would drive small traders out of business.

After several delays, the government in September finally allowed foreign direct investment in the sector to revive stalled reforms and help halt a slide in economic growth.

On Thursday, when the Indian parliament opened for its winter session, opposition politicians demanded a debate and vote on the policy decision and have threatened to halt parliamentary proceedings.

(Reporting by Nandita Bose; Writing by Ranjit Gangadharan; Editing by Matt Driskill)