The Blues are thought to be edging Premier League rivals Tottenham in the race for the Brazil international's signature, with his agent claiming earlier this week the European champions had tabled a 25million euro (£19.8m) bid for the 20-year-old.
Luigi maintains they are yet to receive any concrete bids but has revealed an enquiry has been made over the availability of Oscar for 20million euro (£15.7m).
Luigi was unimpressed by the proposal, telling Radio Gaucha: "We received an email today [Saturday], but it's a long way off being done.
"The proposal wasn't as good as expected. We think Oscar is worth more than €20million.
"It wasn't an offer; it was more like an enquiry. We are only saying that the numbers have to change."
Oscar, capped six times for his country, is regarded as one of the best young talents in Brazil and he has been named in their Olympics squad.
The playmaker has impressed since joining Internacional from Sao Paolo two years ago.