Companies awarded blocks in three rounds of India's New Exploration Licencing Policy are expected to invest $3 billion in exploration, junior oil minister Santosh Kumar Gangwar said on Tuesday.

He said 70 exploration blocks--including 16 onland, 30 in shallow water and 24 in deep-sea regions--had been awarded to Indian and foreign companies since 1999.

In the last three years, exploration firms, including state-run and foreign companies, had spent $1.5 billion in exploration, he said.

"The initial inplace hydrocarbon accretion in the last three years was of the order of 570 million tonnes of oil and oil equivalent of gas," he added.

India is expected to announce the fourth round of the NELP this year and expects large oil companies to submit bids as significant gas discoveries including a reserve of nine trillion cubic feet have been announced in recent months.