Formula One leaders are ready to listen to their teams after presenting a wide-ranging reform package from 2021.
Ross Brawn, F1's managing director for motorsport, told Sky Sports UK that nothing was cast in stone but changes were needed to bring in possible new parties such as Porsche and Aston Martin.
"We have put our ideas to the teams and asked them to consider them carefully," Brawn said after he and F1 boss Chase Carey presented their proposals to the teams on Friday at the Bahrain Grand Prix.
"This is our view of where it should be and, if you come back to us with better ideas or considerations we haven't made, then of course we'll discuss them," he said in an interview to be broadcast later on Saturday.
The plans include a budget cap of reportedly $US150 million ($A210 million) for teams, simpler and cheaper engines and a more-balanced distribution of F1 income.
"We have to put that drawbridge down so we can get new suppliers in," former team principal Brawn said.
The two biggest teams, Ferrari and Mercedes, are said to be the main opponents of the proposals, with Mercedes motorsport chief Toto Wolff naming the cost-cap figure as "not reachable". But he welcomed the proposals being on the table and was ready to work on a compromise.
Ferrari are yet to comment but president Sergio Marchionne has threatened in the past to quit F1 in the event of big changes.
However, the Scuderia appears to continue receiving more money than other teams because of its iconic status in the sport, and being the only team to have participated in every F1 season.
Smaller teams have been more positive, and there has also been a thumbs-up from Aston Martin president Andy Palmer.
"These prospective changes support many of the requirements needed for Aston Martin to enter the sport as an engine supplier. This is a very positive step in the right direction," he tweeted.
F1 bosses are set to hold individual talks with the team before a new meeting in late April with all parties.
