Bloomberg said in a report published on Thursday that IndiGo was in talks with Airbus to order 200 additional A320neo jets valued at about $20.6 billion, citing people familiar with the plans.
"Rumours of a deal are unfounded," an Airbus spokesman told Reuters, but added, "We are always in talks with our customers."
Bloomberg said the deal could be announced as early as next week at the Farnborough International Airshow, adding that while IndiGo had talked with Boeing Co, the airline's preference was to stick with Airbus.
Sakshi Batra, a spokeswoman for IndiGo, declined to comment on the report.
Reuters reported on Wednesday that Airbus is sprinting to line up preliminary orders for a revamped version of its A330 jet and is on stand-by to make an announcement at Farnborough.