Sen, 61, has challenged the order of the Chhattisgarh High Court, which had rejected his bail plea on February 10.
A professional doctor and a pass-out of the prestigious Christian Medical College (CMC), Vellore, Sen has sought bail contending that the trial court has erred in convicting him when there was no substantial evidence.
A bench of justices H S Bedi and C K Prasad had on March 11 agreed to hear Sen's plea and had sought the response of Chhattisgarh government within four weeks.
Opposing Sen's bail plea, the state government in its affidavit had said that the activist should not be granted any relief as he has deep links with hardcore Naxalites.
"He (Sen) provides active support and co-ordinates in spreading the base of CPI (Maoist) in the country. Apart from providing logistic support, he exchanges information and material directly and indirectly with the Naxalites in the area of Chhattisgarh, West Bengal, Andhra Pradesh, Maharashtra, Bihar, Jharkhand and Orissa and propagates Naxal ideology," the affidavit filed by the state government said.
According to the state government, Sen helped Naxal leaders in arranging accommodation in Raipur and through his wife Elina Sen also helped open bank accounts of hardcore Naxalites Shankar Singh and Amita Shrivastava.
Sen, vice-president of People's Union of Civil Liberties, was convicted for sedition and sentenced to life imprisonment along with Naxal ideologue Narayan Sanyal and Kolkata businessman Piyush Guha for colluding with the Maoists to establish a network to fight the state.
Sen's conviction and sentence had led to outrage in many quarters, including international human rights bodies.
Family members of Sen, PUCL activists, and two members of the European Union were present in the high court during the hearing. The EU had earlier sought the high court's permission to attend the hearings.