BNP Chairperson Begum Khaleda Zia filed a bail petition on Tuesday with the High Court in Zia Charitable Trust graft case.
Khaleda's counsels moved for her bail for the second time as the Appellate Division in December last rejected the previous plea.
Khaleda will go abroad for treatment if she gets bail this time, said her lawyer Joynal Abedin.
"She is critically ill and needs better treatment than what is provided by Bangabandhu Sheikh Mujib Medical University doctors," said Sagir Hossain Leon, another lawyer of the BNP chairperson.
The petition may be heard at the High Court bench comprised of Justice Obaidul Hassan and Justice AKM Zahirul Hoque, Leon added.
Earlier on Tuesday, BNP Secretary General Mirza Fakhrul Islam Alamgir and Awami League General Secretary Obaidul Quader also talked to the press on Khaleda's release.
Fakhrul claimed that he did not phoned Quader to request for the BNP chief's release. However, Quader said he has the record of the phone call.
"We have not talked about anything about parole so far. He [Quader] should realise how logical it is to mention that," said Fakhrul.
Journalists asked Fakhrul whether the BNP would consider applying for parole if the court again turns down Khaleda's bail plea.
In reply, Fakhrul said, "It is totally up to her [Khaleda] family."
In the meantime, Quader said, "Why would I lie? Fakhrul called me recently and requested to talk with the prime minister over Khaleda's release. I talked to the premier as he requested."
"He [Fakhrul] requested me. Does he now want to prove that he did not? If so, I will give the proof. I have the record of the conversation. I do not want to humiliate him," the Awami League leader said.
He commented that the BNP is not "sincere" about the release of the party chief. "Rather, the party leaders are trying to make political gains in the name of Khaleda's release."
Former prime minister Khaleda Zia, who is serving a 17-year jail sentence in two corruption cases, has been receiving treatment at the Bangabandhu Sheikh Mujib Medical University since April last year.
BNP leaders have been demanding her release, claiming that she is not getting proper treatment there.
Meantime, Awami League leaders said that they have nothing to do over Khaleda's bail as it is under the court's jurisdiction. They, however, said the government may consider if Khaleda applies for parole.
On December 12 last year, the Appellate Division rejected the incarcerated BNP chief's bail petition in the graft case.
The court also ordered the Bangabandhu Sheikh Mujib Medical University authorities to ensure advanced treatment for her in line with the medical board's recommendations after getting her consent.
Khaleda was jailed by a Dhaka special judge's court in Zia Orphanage Trust graft case on February 8, 2018, and sent to the erstwhile Dhaka Central Jail in Old Dhaka.
Later, she was transferred to the Bangabandhu Sheikh Mujib Medical University for treatment.