Red Bull's currently-dominant 2011 package features a "significant improvement" for the Shanghai weekend.
"Yes, we are currently ahead of the others, but they are moving quickly and things could be different very soon. That's what we have to avoid," the Austrian is quoted by AS newspaper.
"We will introduce a significant improvement in China. I cannot say what it is, but it is necessary because standing still in F1 is tantamount to stepping backwards," added Marko.
Regularly accused of favouring back-to-back pole and race winner Sebastian Vettel, Marko also insisted that Mark Webber is being given identical chances to drive to the top at the wheel of the sister RB7 car.
"Last year it was Vettel struggling in the first two races, as fortune can be cruel," he said. "I would say that Sebastian's misfortune at the beginning of 2010 was worse than it has been for Mark this season."
Last year it was Vettel struggling in the first two races, as fortune can be cruel
Renault driver and Sepang podium-getter Nick Heidfeld said he thinks Vettel, 23, is in better form than ever.
"I don't know if he sees it that way, perhaps for him it's the same as always," the German veteran told sport1.de.
"But viewed from the outside you can say he is a bit more relaxed and is a bit more experienced. So far he has done a flawless season," added Heidfeld.