The company aims to open its IPO on November 10 to raise more than 15 billion rupees ($325 million) to fund its expansion, the sources said.
"The bankers, HSBC, Citi, and Morgan Stanley, with bases in the U.S. have asked Oil India not to invest IPO proceeds in Iran and Sudan," said an oil ministry official with knowledge of the IPO plans who did not wish to be identified.
The state-run firm holds a 10 percent interest in a pipeline in Sudan and 20 percent in the offshore Farsi exploration block in Iran.
Another ministry official said Oil India was expected to give such an assurance to attract institutional investors from Western countries.
A third official confirmed the development.
"Bankers know the pulse of overseas institutional investors. They have prepared the list of interested parties and are expected to begin discussion with them from October 13," the third source said.
The move by the banks is a sign that the U.S.-led campaign to isolate Tehran over its nuclear programme is making it more difficult to invest in the Islamic Republic. ($1=46.3 rupees) (Reporting by Nidhi Verma; Editing by John Mair)
