India had been part of the $7 billion so-called "peace pipeline" project, but stayed away from talks in September saying it wanted to agree transit costs through Pakistan on a bilateral basis first.
Iran and Pakistan had agreed on a revised price formula and a new price review mechanism in December which updated terms reached in 2006 during long-running negotiations on the project.
"The last round of talks on the export of Iranian natural gas to Pakistan started this morning," ISNA said, without citing a source.
Hojjatollah Ghanimifard, the oil minister's special representative to the pipeline talks, said on Wednesday during the two-day talks a date would be set to finalise the deal.
"In this meeting, the two sides will also set a date to sign the (final) deal," the official said, state media reported on Wednesday.
Iran, which sits on the world's second biggest gas reserves, imports roughly about as much gas as it exports. U.S. sanctions have been a factor hindering Tehran's export strategy, as it tries to become a major gas exporter.
Ghanimifard had previously said he hoped that the commencement of gas delivery would start five years after the contract was signed, adding that both Iran and Pakistan would welcome India anytime it decided to join the project.
