Fernando Alonso believes Sebastian Vettel has a chance of winning the Formula One drivers' championship with Ferrari this season.

Four-time champion Vettel finished third in the standings at the end of his first year with the Italian team in 2015, behind Mercedes duo Lewis Hamilton and Nico Rosberg.

The former Red Bull driver finished on the podium at the season-opening Australian Grand Prix, and, after mechanical difficulties stopped him from racing in Bahrain, was second in China last weekend.

Vettel is the closest to overthrowing Mercedes' hegemony, according to Alonso, but the McLaren man believes his team, as well as Renault, can challenge.

"He's in a good position, he's young and motivated and the car is not far off the best. That's good," Alonso told AS.

"I think the trend in Formula One now is that Mercedes, Ferrari, Renault and McLaren Honda can win the championship because the other private teams won't.

"With an engine of that calibre the mother factory can win the title on its own, so for the Mercedes and Ferrari drivers it's a great opportunity and I'm sure one of them will win the title.

"If Renault improve sufficiently and McLaren Honda do as well they'll have the chance to win, but other than that, the private teams are out of the running.

"The level of power we have at the moment and our lap times are much better than the ones other teams were managing in their second year with the turbo."

Alonso also spoke out on the state of F1, stating drivers need to be given a greater role in potential rule changes by Formula One Management (FOM) and the International Automobile Federation (FIA) after a number of controversial decisions.

"Now we have the GPDA [Grand Prix Drivers' Association] and all of the drivers are united in the idea that we want to change things because the decisions taken last year in F1 were opposed to what we believe should be in the interest of this sport," he said.

"As such, hopefully the situation will change but, why did it have to come to this point? FOM and the FIA do everything, normally they do it well and they will continue to do so, but there are some things that could be improved or that the drivers can be asked to assess.

"We don't want to write the rulebook, we're not able to do that. But if they want to change the rules and they asked our opinion maybe we'd say to them, 'perfect'. Or on the other hand, 'that's not the way it should be' and offer an explanation."