"RPL commenced its crude processing (today). The secondary processing units are now under synchronization and commissioning," a company press statement said.
"The entire refinery complex is expected to attain full capacity shortly," it said but did not give a specific date.
The new unit has come up adjacent to Reliance's existing 660,000 bpd (33 million tons a year) mostly-for-exports refinery at Jamnagar.
"RPL refinery has been completed in 36 months from concept to commissioning, which is a new benchmark for building a grass-root refinery of this scale and complexity," the statement said.
Company's Chairman Mukesh Ambani said: "Commissioning this large and complex refinery in record time... yet again demonstrates the strength of our project management skills."
"We, at Reliance, continue to be committed to the long term potential of the refining sector. We will leverage our competitive advantages of scale, complexity and capability to process a wide range of crude oils and flexibility to produce high quality transportation fuels," he said.
RPL, in which the US energy major Chevron Corp hold five per cent stake, will produce petrol and diesel complaint to Euro-IV emission norms.