Maharashtra Home Minister Anil Deshmukh resigned on Monday after the Bombay High Court ordered a CBI probe into the allegations of extortion against him by former Mumbai police commissioner Param Bir Singh.

Deshmukh submitted his resignation letter to Chief Minister Uddhav Thackeray, NCP minister Nawab Malik told reporters.

Deshmukh also tweeted a copy of the letter, in which he said the high court had passed an order for a preliminary probe by the CBI into the petition filed by advocate Jayshri Patil into the allegations.

"I don't have the moral right to continue in office after the court order.I have decided to quit. Kindly relieve me from my post," Deshmukh's resignation letter said.

After the court order, Deshmukh met NCP president Sharad Pawar and expressed his desire to step down as he felt it was inappropriate to continue in office after the CBI steps in, Malik said.

"Deshmukh went to hand over the letter to Thackeray after Pawar gave his "green signal" to quit," Malik said.

Singh's allegations are baseless but the party respects the court and hence the minister will quit, Malik said, adding the truth will come out.

"The state government has already ordered a probe by a retired judge into the claims but we respect the judiciary and after the court orders, Deshmukh himself said he doesn't wish to continue," Malik said, referring to his party colleague.

After Deshmukh's resignation the home department will be with the chief minister, who would decide after consulting the MVA allies on who would be the new home minister, he said.

There is speculation that Dilip Walse Patil, another NCP minister, may get the Home portfolio.

State BJP chief Chandrakant Patil said he is happy that Deshmukh has quit, adding there will be many "shocking revelations" in the CBI probe.

"Those who make mistakes should be punished or else democracy won't be strengthened. Many skeletons will tumble out after the 15-day CBI preliminary parobe," he said.