Iran has told Pakistan it is contractually obliged to complete the gas pipeline project.
The warning from Iranian oil ministry came a day after Pakistan's oil minister, Shahid Khaqan Abbasi, said work on the pipeline was not currently possible.
Abbasi said that Pakistan was forced to take the decision because of sanctions imposed by the United States and the European Union on Tehran over its controversial nuclear drive.
According to Dawn News, Iran's deputy oil minister, Ali Majedi, said Tehran has carried out its commitments and also expected Pakistan to honour its own.
Majedi, rejecting the sanctions argument, said Pakistan was fully aware of the situation and the issue of sanctions, before signing the contract.