DAZN’s Spanish broadcaster Ricard Jove reported during the Dutch MotoGP weekend that Marquez had “offered himself” to the rival manufacturer.
But he reported KTM’s response: “They have rejected him due to the ‘strategy’ of the brand.”
He then added: “That's what the KTM boss has said and, by the way, I don't believe it either. It can be only an initial strategy for the negotiation.”
Marquez has endured a torrid year-and-a-half on an underperforming Repsol Honda which has frequently resulted in him over-riding and crashing, causing a litany of physical issues.
His big-money contract with Honda expires at the end of 2024, by which time he will be 32, but he is constantly linked with switching teams.
"It's a lie,” he told DAZN about offering himself to KTM.
“I've heard this rumour because one of my mechanics has joked and it's a complete lie.
“Yes, it's true that when the factories see that a rideris in difficulty, they ask and in this case I'm still committed to Honda, I have a valid contract, so nothing.
“Continue working to improve the project for the future.”
The link between Marquez and KTM is Red Bull. Their mutual sponsor - a powerful force in motorsports - is often cited as wanting to unite Marquez and KTM.
Marquez was asked if any other teams had approached him about a contract in 2025?
"Well, no. I've already told you,” he said.
“When a driver is in difficulty and this is always the case, even if there is a contract or not, there are always contacts between the trucks, but in this case my contract is with Honda and I'm still calm here."
Marquez is stuck on six MotoGP championships and his hopes of glory this season were shattered early but the combination of crashes and missed rounds.
He withdrew from the Dutch MotoGP at Assen just hours before the race, citing injuries suffered a week earlier at the Sachsenring which had been aggravated.
After eight rounds of 2023, he is yet to complete a grand prix.