The total cost of developing the three oil fields, in which the Indian unit of Britain's Cairn Energy owns 70 percent, has increased to $3.8 billion from $2.93 billion, the Business Standard newspaper reported.
The Press Trust of India reported that ONGC would invest $350 million more into the fields operated by Cairn India.
The revised investment plan for Mangala, Bhagyam and Aishwariya oilfields includes $940 million for a pipeline to evacuate the crude to coastal Gujarat.
ONGC owns the remaining 30 percent in the venture and has the liability to pay the royalty on the entire crude production.
The state-owned refiner will ask the Indian government to reimburse the royalty payment it has to pay for Cairn as the new plan is economically unviable, the newspaper quoted an unnamed ONGC official as saying.
India is Asia's third-largest oil consumer. It imports 70 percent of the oil it consumes and is keen to tap domestic reservoirs to help bring down its dependence on imports.