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% 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.