Lopez: Honda, Lada, Volvo can all challenge Citroen in 2016 WTCC

Citroen has strolled to the last two manufacturers' titles in the championship, while Lopez clinched the drivers' crowns in similarly crushing fashion - with 20 victories in 48 races.

But ahead of its withdrawal from the WTCC at the end of 2016, the marque has cut its factory assault from four cars to two - with nine-time World Rally champion Sebastien Loeb and Ma Qing Hua dropped from its line-up.

By contrast, Honda has expanded to three-cars this year with 2012 champion Rob Huff and Norbert Michelisz joining the incumbent Tiago Monteiro at the JAS Motorsport-run team, Lada has refreshed its line-up and Thed Bjork and Fredrik Ekblom will front Volvo's assault.

With a reinvigorated chasing pack, Lopez told Autosport he was anticipating a much tougher fight to capture a third-consecutive title.

"I think yes [it will be more challenging]," said the Argentinian. "Especially as the competition has been growing since we started.

"We've [Citroen] raised the level of the series and everyone has been pushing to catch up. Honda had progress on the car and put Rob Huff, and Michelisz, in the new line-up.

"I think that could be a really strong team this year.

"We don't really know Volvo's level. They've been developing the car for a while already so I think it's going to be a good car. They have a chance to win races in their first year.

"Lada will be a strong team as well; they have [Hugo] Valente, [Gabriele] Tarquini and [Nicky] Catsburg who is a great driver as well. I think they can improve the car.

"I think it's going to be a different year, the competition is going to be really strong. This year is going to be really tough."

Lopez acknowledged that his and Citroen's quest to defend their titles would be made more difficult by the increase of success ballast to 80 kilograms, but insisted he was relishing the prospect of a harder fight for honours.

"The most important aim is to secure the constructors' championship and it will be hard work to defend," he said.

"I'm really looking forward to it. I love the first race of the year, it creates a lot of expectation. You don't know the level of your car compared to the others. It's different.

"It will be really interesting to see what happens, especially as this season we're carrying 80kg of ballast."