The Chinese government submitted a preliminary report to the Pakistani government seeking more information on the project.
The report was submitted after President Pervez Musharraf, on his recent visit to China, asked his Chinese counterpart Hu Jintao to join the project.
Subsequently, Pakistan sent a proposal asking China to join the project in case India pulls out, the Daily Times quoted a senior petroleum ministry official as saying.
Pakistan has also asked the Chinese government to conduct a feasibility study for the pipeline project.
There has been no progress on the project since talks were held between India and Pakistan in Islamabad in April. The Indian government is yet to respond on the issue of the transit fee to be paid to Pakistan for Iranian gas transported across its territory.
Foreign Minister Shah Mahmood Qureshi, who also holds the petroleum portfolio, is expected to hold talks on the project when he visits India on June 27.
The petroleum ministry official said that if India pulls out of the project, the additional gas volume of 1.05 billion cubic feet per day would either be consumed by Pakistan or sold to China.
Iran has no objection to China joining the pipeline project if India pulls out of the venture, the official said.
