India said on Thursday that it is engaged in efforts to bring back an alleged Indian spy sentenced to death in Pakistan, who it reiterated is innocent of the charges hurled at him.

External Affairs Ministry spokesperson Gopal Baglay, fielding a slew of questions, also said India has no knowledge of where Kulbhudhan Jadhav has been kept in Pakistan or his condition due to Islamabad's refusal to provide consular access to him.

"We are engaged in the efforts (for his release)... I won't like to speculate on the steps about the future at this stage, or who we will talk to and who will not talk to," he said.

Jadhav, a former Indian naval officer, has been sentenced to death by a Pakistani military court for espionage and waging war against Pakistan. India has warned that if Pakistan executes Jadhav, who was arrested in March 2016, it would amount to "premeditated murder".

Asked if the government had any information about Jadhav, the official said New Delhi was not aware.

"We have no information and the Pakistan government has also not shared with us his location and how and where he is held and what his condition is," Baglay told the media.

He reiterated that there was no credibility to Jadhav's secret military trial and described as "baseless" the charges of espionage and waging war against Islamabad levelled against him.

He said India had made 13 requests to Pakistan till April 10 for consular access to Jadhav, but Islamabad denied each of them.

Baglay reiterated that it would be considered "premeditated murder if the indefensible sentence is carried out".

He trashed the secret trial by the Pakistani military court as "completely opaque". "There is no credibility in the trial."

Baglay said that not giving consular access to Jadhav "itself exposes the hollowness of the charges".

"In the light of all this, we have said clearly that the proceedings against Jadhav are farcical. The verdict is indefensible. No due process has been followed. It is a violation of the basic normal of international relations and justice," he added.

Asked whether the sentence could be linked to the disappearance of a retired Pakistani military officer - Lt Col Habib Zahir -- in Lumbini, Nepal, Baglay said he had "no information" about the case.

Baglay also said that Jadhav was "legally doing business" in Iran's Chabahar port and the issue has been discussed with Teheran.

"We have discussed the issue with Iran. He was legally doing business there," he said, adding that he had no information about the progress of investigations.

Asked about Jadhav possessing a fake passport under an assumed name, of Hussein Mubarak Patel, Baglay said that they had not seen the passport.