NEW DELHI (AFP) - India's sports ministry on Wednesday piled pressure on the chief of the country's cricket board to quit on "moral grounds" over a widening betting and spot-fixing scandal that has rocked the sport.

N. Srinivasan, head of the Board of Control for Cricket in India (BCCI), is under fire after his son-in-law Gurunath Meiyappan, was arrested for allegedly betting on Indian Premier League (IPL) matches.

The BCCI on Tuesday set up a three-member inquiry commission to look into complaints against Meiyappan, an executive at the Chennai Super Kings IPL team, who are owned by Srinivasan's biggest company, India Cements.

"The ministry of youth affairs and sports has observed with considerable disquiet, the reports about match- and spot-fixing in cricket," said a statement from the ministry.

"As there is a conflict of interest in this inquiry, the BCCI president should tender his resignation on moral grounds, pending the outcome of the inquiry."

Earlier on Wednesday, IPL chairman Rajeev Shukla said "it would be good" if Srinivasan - who is managing director of India Cements - stayed away from the inquiry proceedings.

Also on Wednesday, a court in Mumbai extended the police custody of Meiyappan till Friday to enable investigators to interrogate him further.

Betting on sports other than horse racing is a crime in India.

Meiyappan's arrest followed similar action against former India international and World Cup-winning bowler Shanthakumaran Sreesanth and two team-mates in his IPL franchise the Rajasthan Royals - Ankeet Chavan and Ajit Chandila.

The trio have been sent to judicial custody in New Delhi after police accused them of deliberately bowling badly in exchange for tens of thousands of dollars after striking deals with bookmakers.

The police have widened their probe into the scandal, arresting scores of bookies and Bollywood actor Vindu Dara Singh Randhawa.