Pakistani prosecutors had filed the application during the last hearing of the Mumbai attacks case on April 16.
Anti-terrorism court Judge Rana Nisar Ahmed said during today's proceedings at the heavily-guarded Adiala Jail in Rawalpindi that he would give his ruling on the maintainability of the application at the next hearing on April 30.
"The prosecution and defence lawyers presented their arguments on the matter today. The judge said he would rule on the maintainability of the application at the next hearing," Shahbaz Rajput, one of the defence lawyers, told PTI after the hearing held behind closed doors for security reasons.
The prosecution''s application contended that defence lawyers could not present an argument regarding Kasab and Ansari as they did not represent the two men, sources said.
The defence lawyers recently filed an application seeking the start of trial proceedings as soon as possible and recording of evidence against the accused.
The application was filed under Section 403 of the Code of Criminal Procedure and Article 13 of the Constitution, which state that no person can be prosecuted or punished for the same offence more than once.
The defence lawyers' application was apparently aimed at stymieing the prosecution's efforts to gain access to Kasab, the lone surviving attacker involved in the Mumbai incident, and terror suspect Ansari.
Kasab was convicted and sentenced to death by an Indian court. The same court acquitted Ansari, but he continues to be in custody in connection with other cases.
The seven Pakistani suspects, including Lakhvi, have been charged with planning, facilitating and financing the attacks that killed 166 people.
The trial has been marred by repeated delays over technical matters. The judge has been changed thrice and only one of more than 160 prosecution witnesses has testified so far.