It will be Zardari's second visit to Iran since February 27 and comes after officials said a consortium would start work on the pipeline on Pakistani territory on March 11 despite American warnings of possible sanctions.

"President Zardari will visit Iran for the groundbreaking ceremony and it will take place on March 11," foreign ministry spokesman Moazzam Ahmad Khan told reporters in Islamabad.

He did not give further details but a senior Pakistani official told AFP that the ceremony would be held on the Iran-Pakistan border.

Pakistan suffers from a crushing energy crisis, but the United States says it has offered Islamabad alternative solutions to help avoid sanctions.

"We are not in a fix... we are very clear about it that the pipeline is in our national interest being an energy deficient country," Khan said.

"Yes we know about their concerns but hope our friends, including the US, will understand our economic compulsions," said Khan.

Officials have said Monday's ceremony will mark the start of work on the 780-kilometre (485-mile) pipeline earmarked for the Pakistani side of the border, which is said to cost some $1.5 billion.

Although the pipeline on the Iranian side has almost been completed, Pakistan has run into repeated difficulties, both in financing the project and over a US threat of possible sanctions due to Iran's nuclear activities.

Iran eventually agreed to finance a third of the costs of laying the pipeline through Pakistan, with the work to be carried out by an Iranian company.