Ghosn has denied that Renault will quit F1 at the end of 2006

Ghosn said the 2005 champions would stay "if it is in Renault's interest".

He said Renault would regularly review its position after next year because of uncertainty over new rules for 2008.

"At the moment, it is a good investment for Renault. As long as it remains a good investment, we will stay. The day it is no longer, we will go," he said.

Insight: Renault rumblings

Ghosn has previously rejected claims Renault could quit at the end of 2006.

The speculation about Renault's future arose from the decision of lead driver Fernando Alonso, who became the youngest-ever F1 champion at 24 in 2005, to join rivals McLaren in 2007.

For the moment, we are proving through F1 what Renault is capable of, and that the cost of F1 is in fact an investment Carlos Ghosn Renault president

The Spaniard said at the launch of the team's latest F1 car last week that his defection was not down to money but to confusion over Renault's future plans.

And the loss of key sponsor Mild Seven, a cigarette company, at the end of the year has also contributed to speculation about the team's ability to continue competing.

"There will be changes to the rules in 2007/8, which we are analysing, and on an extremely objective basis we will decide on the length of our commitment in light of that," Ghosn said on Thursday.

"For the moment, we are moving forward, we are fighting and, what is very important in my view, we are proving through F1 what Renault is capable of, and that the cost of F1 is in fact an investment."

He added: "I am confident that the team we have at the moment, that won a double championship in 2005, will be fighting for good results in 2006."