McLaren's Dennis is among the team bosses backing the plan
Formula One team bosses have backed plans to expand the calendar to 20 races a year but say that should be the maximum number of grands prix allowed.
The current season has 18 races, after 17 last year and a record 19 in 2005.
McLaren boss Ron Dennis supports the 20-race limit but warned any expansion should not come at the expense of the sport's European winter break.
"I welcome this expansion, and heartily commend (F1 chief) Bernie Ecclestone for spearheading it," said Dennis.
"But I have two provisos; firstly, that the season never expands to more than 20 grands prix, which I regard as a natural logistical limit and, secondly, that we preserve a closed season over the winter.
"The closed season is essential not only for logistical reasons but also in order to stir up a sense of anticipation in the hearts and minds of F1 fans."
Honda chief executive Nick Fry agreed with the plan to expand to 20 races because it gives the sport room to develop commercially.
"I think 20 grands prix is about right," he said. "The balance of traditional circuits in Europe and circuits in new continents is vital.
"Formula One needs to go where the commercial market is and that market is moving from Europe and North America to the Middle East and Asia."
Formula One has two new venues this year, with a European Grand Prix in Valencia and the first night-time race in Singapore, but the US Grand Prix at Indianapolis has gone from the calendar.
This weekend's Bahrain GP, the third round of the season, is currently the only Middle Eastern race but Abu Dhabi is pencilled in for next year while in Asia, India and South Korea are scheduled for 2010.
A third Middle Eastern race could also be on the cards, with Dubai and Qatar interested and already having lavish facilities in place.