Global Motorsport Media
F1's major engine manufacturers want the FIA to drop regulations that guarantee customers for their rivals.
Currently, there are four engine makers on the grid -- Ferrari, Mercedes, Renault and Cosworth.
The latter independent supplier, however, is reportedly fighting for customers for 2012 and beyond, with Williams switching to Renault and rumours HRT could follow Team Lotus in also ending its association with Cosworth.
And for 2014, new supplier Pure intends to enter Formula One with a V6 design, but its boss Craig Pollock is reportedly concerned that he too will struggle to compete with the major manufacturers.
In Singapore, figures for Mercedes-Benz - currently supplying McLaren, Force India and its works team - and Renault, with no fewer than four contracted customers for 2012, sounded unapologetic.
"I am pushing for an open market because we are in Formula One and regulations cannot solve all the problems," said Renault Sport F1's Jean-Francois Caubet.
It should be a free and open market
Mercedes' Norbert Haug agreed: "If five teams choose 'engine x', then they should do so, it should be a free and open market."
The German sounded uncertain that the fifth supplier, Pollock's Pure, will ultimately join the party in 2014.
"This would be very pleasing for all of us, even more competition, but maybe we (will) have less than five, we will see," said Haug.