"Out of five who had bid, we short-listed these three for making detailed presentations on the international best practices in pipeline projects and their proposals," Indian Oil finance director S V Narasimhan told reporters on Wednesday.

"We will finalise the financial consultants by month end or the beginning of September," he said.

The selected consultants would be given time till November to present project models for the execution of the natural gas pipeline project, now estimated to cost over $7 billion given the rise in input costs of products like steel.

The project design would have to address security concerns, a financing model for the execution of the project and work out a formula for ensuring delivery of natural gas at India's border at a price lower than the imported liquefied natural gas (LNG) among other factors.

India is committed to having in place technical, legal and financial consultants ahead of the second round of the India-Pakistan joint working group meeting in Islamabad next month.