Mercedes' support of the plan to increase the engine allocation to five is unlikely to be enough for the rules to be changed.
Motorsport.com understands world champion Mercedes is ready to back the plan as long as the fifth engines are used only during Friday practice.
As reported by Motorsport.com earlier this month, the plan looked set to collapse as it would not get the unanimous support it needs to go through, despite Red Bull boss Christian Horner saying last month that all teams had agreed to the change.
However, Force India deputy team principal says his team, and others like Williams and Lotus, will block the plan because they fear it would increase the costs even further.
"I know it's on the agenda but I have no idea what the wording is. And more importantly I don't know what the cost implications are, because that will be the key to it," Fernley told Reuters at Barcelona.
"That's why Williams wouldn't want it, why Lotus wouldn't want it and why we wouldn't want it."
The plan is set to be discussed in the Strategy Group meeting next week.