Red Bull advisor Helmut Marko believes that none of Mercedes's rivals in Formula 1 will be able to catch up with the constructors' champions anytime soon.
The Silver Arrows started the 2015 campaign in dominant fashion, with Lewis Hamilton heading a Mercedes one-two at last weekend's Australian Grand Prix.
However, Marko has suggested that the German manufacturer will remain unopposed at the top of the sport, while the current rules on engine development remain in place.
He told Speed Week: "We at Red Bull do not believe that, with these restrictions in this form, any other manufacturer will ever catch up with Mercedes.
"If you do not have that engine, you have no chance at the moment.
"I can't imagine that Honda will catch up in the medium term. Ferrari's performance must also be seen relatively: they are not closer, they are just better than last year."
Red Bull finished second in the 2014 constructors' championship.
