Renault have warned late-paying Formula 1 teams they risk having their engine supply withheld if matters are not resolved in the next few weeks.
Renault supply world champions Red Bull, sister team Toro Rosso, Lotus and Caterham.
Jean-Michel Jalinier, Renault Sport's F1 head, said the deadline for settling the issue was "just weeks away".
He said: "We'll have to address the situation and take decisions, because it's something we can't carry forward."
Jalinier did not mention any customers by name but world champions Red Bull do not pay for engines as they are the works team.
Toro Rosso are also owned by the multi-billion-pound Austrian energy drink company. Their team boss Franz Tost said: "As far as I'm aware, we've paid everything."
Lotus trackside operations director Alan Permane said: "We are 100% up to date with our payment schedule."
And Caterham team principal Cyril Abiteboul said: "It's a confidential issue but I'm happy since we are settled with invoices with Renault Sport F1."
Renault have also suffered a performance deficit to the rival Mercedes power unit following the introduction of the new hybrid engines this year.
"Our resources are coming from two sources. One is Renault, and we have been able to secure the right resources, and the other part of it is coming from the teams, because we are selling the engines to the teams," said Jalinier.
"On this part I must say we are not at an acceptable situation, because some of the teams are just late in payments, and at the time you need to spend resources to catch up you cannot afford to have those [late] payments."
Asked whether Renault's response could include withholding engines, Jalinier added: "That is an option. You first need to work with your team and get back to some kind of financial situation."
Neither Lotus, who experienced financial difficulties last year, nor Caterham have scored points so far this season.