Honda is upping its Formula 1 budget for 2020, according to Italy's La Gazzetta dello Sport.

The move follows pressure on the Red Bull-Honda alliance from Max Verstappen and his father Jos, who have indicated they could be on the move for 2021.

The Italian sports newspaper claims that Honda is investing EUR 140 million on development of its 2020 engine, in order to catch Ferrari and Mercedes.

"The big teams still have an advantage over us," Honda F1 boss Toyoharu Tanabe told Spain's AS newspaper.

La Gazzetta dello Sport also reported that Honda has increased its F1 workforce from 250 people in 2017 to 450 this year.

And team boss Christian Horner said the debut of a brand new Mobil 1 fuel this weekend is a sign that the Red Bull-Honda partnership is working well.

"The great thing about Honda is that they are fully focused on working with Red Bull and Toro Rosso," he said.

"That is significantly different to what we were used to before. Our former engine supplier (Renault) used another fuel and oil partner for their factory team.

"But we are involved in all of Honda's development, and that includes the fuel and the lubricants. It's a true partnership," Horner added.

ExxonMobil's technical boss David Tsurasaki confirmed at Suzuka that the new fuel features chemicals "that have never been used in Formula 1 before".