13th team must pay 19m euro entry deposit – Ecclestone
But according to London's Evening Standard, the last spot on next year's grid will only be filled if a team can prove it is healthily funded.
FIA president Jean Todt's son Nicolas recently withdrew the 2011 application of his GP2 team ART, but others including US group Cypher and Spanish Le Mans team Epsilon Euskadi, and possibly the Serbian hopefuls Stefan GP, remain interested.
"We have told them that if they can't put 16 million (British pounds) in now we don't want them. If they can't find that now there is no way they are going to run," said Ecclestone.
The 79-year-old Briton's attitude is no doubt fuelled by the performance of new teams Lotus, Virgin and HRT, admitting he is "not happy" with their pace.