Replying to a debate on the governor's address in the assembly here, Singh said the government had decided to investigate all "benami" land transactions.
"It's quite known that there were largescale land irregularities during the BJP regime. There will be a speedy inquiry and the guilty will be penalised," he said.
The Congress, when in opposition, had been pointing fingers at top figures in the government led by Prem Kumar Dhumal on charges of alleged involvement in illegal property transactions.
An 80-page corruption "chargesheet" the Congress gave to President Pranab Mukherjee in August alleged that the Himachal Pradesh Cricket Association had provided several pieces of land in the state.