Till now, four rounds of negotiations have been completed and the last one was held in March in Tehran where both countries discussed draft text of the pact.
"Both sides have tentatively agreed to hold the fifth round of talks here this month," the official added.
Unlike in a free trade pact, where two trading partners significantly reduce or eliminate duties on maximum number of goods traded between them, PTA involves removal of duties on certain identified products.
"The PTA may not help India in bypassing trade sanctions being imposed by the US on Iran, but in the long run, Iran is an important market for Indian exporters," Biswajit Dhar, a professor of economics at Jawaharlal Nehru University, said.
"With a carefully designed PTA, strategic products such as leather, textiles and ready made garments, which attract very high duties in Iran can become naturally competitive and India will be able to leverage its export strengths," he said.
Federation of Indian Export Organisations (FIEO) said Iran holds huge export opportunities in sectors such as agriculture, chemicals, machinery, pharmaceuticals, paper and paper products, man-made fibre and filament yarn and essential oils.
"The PTA will help India in its long run to increase exports," FIEO DG Jay Sahai said.
India's exports to the Persian Gulf nation in 2017-18 were worth USD 2.65 billion, while imports were valued at USD 11.11 billion. The trade imbalance is mainly because of India's import of oil from Iran.
India, the world's third-biggest oil consumer, meets more than 80 per cent of its oil needs through imports. Iran in 2017-18 was its third-largest supplier after Iraq and Saudi Arabia and meets about 10 per cent of the total needs.