Fiat Chrysler chief Sergio Marchionne said Thursday he expects a new merger in the auto industry by 2018, without confirming reports he proposed a tie-up with General Motors.

"It is a personal opinion, certainly, but I am sure that there will be a merger between now and 2018" in the auto industry," Marchionne was quoted as saying by Italian news agencies during a visit to Fiat Chrysler Automobiles's (FCA) Melfi factory in southern Italy.

He did not mention which carmakers he saw as tying the knot.

And when asked about reports he sent an email to the head of General Motors to suggest a merger, Marchionne declined to confirm he made the offer.

"Emails, I receive and I send many, one doesn't speak about such things like that," he said. "When there is something to announce, we'll do so."

Fiat and GM have a bit of a history, with the largest US carmaker taking a 20 percent stake in Fiat and the Italian company a five percent stake in GM as they launched a number of joint ventures in 2000.

But their relationship soured and in 2005 their alliance ended.

Marchionne, who took over Fiat in 2004, tried to snap up GM's European unit Opel in 2009 when the US company was on the ropes and filed for bankruptcy protection.

Marchionne was the architect of the merger between Fiat and US carmaker Chrysler, which was finalised in 2014.

Marchionne and Italian Prime Minister Matteo Renzi visited the Melfi factory, which has added 1,550 jobs this year as it has begun to turn out new Jeep Renegades, a small 4x4 SUV.

The factory, which now employees 7,500 workers, is expected to turn out a record 400,000 vehicles this year.

FCA returned to the black in the first quarter of this year with a profit of 92 million euros ($101 million) thanks in large part to rising US sales.