State Bank of India, the country's top lender, has cut its key lending rate, or base rate, by 5 basis points, R. Venkatachalam, deputy managing director at the bank, told Reuters on Wednesday.

The base rate now stands at 9.7 percent and will be effective Feb 4, the bank said in a statement.

The Reserve Bank of India cut a key policy rate by 25 basis points on Tuesday to help support an economy set to post its slowest annual growth rate in a decade.

"It worked out to only 5 basis points. We are passing on the entire benefit," Venkatachalam said.