However, the Congress has denied the charges.
MP BJP unit president Nandkumar Singh Chauhan at a press conference last evening presented documents, running into 160 pages, claiming to be from the Income Tax Appellate Tribunal and having evidence of payment of huge sum of money to Singh by a Bhopal-based builder.
Also Read
"The entries in the diary were made before 2003 and against the transaction 'CM and HCM' had been written. Obviously, at that time Digvijay Singh was the Chief Minister," he said.
Besides Chouhan, state higher and technical education minister Uma Shankar Gupta and transport minister Bhupendra Singh were also present at the press conference.
The BJP leaders said they will soon meet the Income Tax Commissioner to demand further probe into the matter.
Digvijay Singh could not be contact for his reaction on the issue.
However, refuting the allegations, state Congress unit's chief spokesman K K Mishra said the charges were "politically motivated and aimed at settling scores with him (Singh), violating laid down political traditions."
If the BJP has any credible evidence against Congress leaders, then instead of politically blackmailing them, it should put them behind the bars, he said.
After the names of (Shivraj Singh) Chouhan and his family members surfaced in the MPPEB scam, the Chief Minister is feeling insecure in his chair and this is an attempt to blackmail Congress leaders, Mishra alleged.
Earlier also an FIR was registered against Singh and others in connection with the alleged irregularities in number of appointments in Vidhan Sabha during his tenure.
The Congress General Secretary has been demanding from the government to handover the matter along with the MPPEB scam to the CBI for detailed investigation.
The BJP's allegation has further intensified the political battle in the state.
Earlier, Singh had attacked Chief Minister Shivraj Singh Chouhan alleging his involvement in the MPPBE scam for admission to medical colleges and recruitment in government jobs.