Turkmenistan aims to deliver natural gas through Afghanistan, Pakistan and India from its vast domestic reserves. The project is seen as a rival to plans from Iran through its so-called Peace Pipeline.
Sapar Berdiniyazov, the Turkmen envoy to Islamabad said both sides could reach a decision on pricing for the pipeline by next month.
"(The) framework agreement between the four countries has already been signed in Ashgabat, the capital of Turkmenistan," he was quoted by the Associated Press of Pakistan as saying.
TAPI is favored by Western powers over the Iran's pipeline project.
U.S. Secretary of State Hillary Clinton during a July visit to India called on Asian countries to work together to "create a new Silk Road" of transnational networks of economic and transit connections.
"That means building more rail lines, highways, energy infrastructure, like the proposed (natural gas) pipeline to run from Turkmenistan, through Afghanistan, through Pakistan into India," she said.
Ashgabat aims to deliver about 1.1 trillion cubic feet of gas each year through the pipeline when it goes online in 2014.