Red Bull are already working with Honda, amid rumours that they will go racing together in 2019.
Already next year, given the Japanese marque's breakup with McLaren, Honda will supply engines exclusively to the Red Bull junior team Toro Rosso.
Dr Helmut Marko revealed to German broadcaster Sky that Red Bull Technology is lending a hand.
"Right now, we're working hard with Honda to make this a competitive package with Toro Rosso," he said.
"We are very pleased with the progress Honda is making and will continue to make until the start of the season."
It is the strongest sign yet that, with Red Bull's Renault engine deal ending after 2019, a Red Bull-Honda tie-up for 2019 is probable.
Marko said that Red Bull will support Honda "for example with the facilities that Red Bull Technology has".
The 74-year-old said that Red Bull will then stand back and track the progress of the Toro Rosso-Honda package next year.
