MONZA, Italy (Reuters) - Fiat Chrysler Automobiles (FCA) FCHA.MI boss Sergio Marchionne said on Sunday that seeking a tie-up with General Motors GM.N was a "high priority" and such a deal would also be the best strategic option for its U.S. rival.

Fiat Chrysler CEO Sergio Marchionne (L) shakes hands with Formula One supremo Bernie Ecclestone during the Italian F1 Grand Prix in Monza September 6, 2015. REUTERS/Max Rossi

GM’s board rebuffed a merger proposal from the Italian-American carmaker earlier this year. That has not stopped Marchionne from wooing his bigger competitor as he seeks to reduce the number of players in the industry and share the prohibitive costs of building greener and more intelligent cars.

“That discussion remains a high priority for FCA,” he told journalists on the sidelines of the Formula One Italian Grand Prix in Monza, northern Italy.

He did not want to discuss the next steps FCA might take or their timing, but said a merger with GM would “be the best possible strategic alternative for us and for them. General Motors does remain the ideal partner for us and we represent a not easily replaceable alternative for them.”

Marchionne declined to comment on whether FCA would pursue a hostile bid for GM.

“I have zero comment on that issue. I’m not a good forecaster of the future when it comes to that,” he said.

He added he had not gone out to speak to any GM shareholders about the issue, but may have spoken to some of them by accident because of the companies’ overlapping investor base.

Marchionne said he had had a brief chat about his GM ambitions with Italian Prime Minister Matteo Renzi, but added that while Renzi “may have his personal preferences, he’s never expressed it”.

Addressing concerns that such a merger could mean job cuts, he said: “The implication of any tie up of that caliber would be absolutely zero on the manufacturing infrastructure of the two companies.”

GM has repeatedly said it prefers to go it alone. The U.S. automaker said last week that remained the best strategy to create value for its shareholders, even after an in-depth review of a possible merger with FCA.