Mercedes boss Toto Wolff says speculation that one team in the Formula 1 paddock has “massively” exceeded the cost cap limit from last year makes the matter a “heavyweight” issue.

A developing story at the Singapore Grand Prix revealed that two teams were believed to have breached the 2021 cost cap, with Aston Martin and Red Bull suggested to be the main culprits.

Red Bull team principal Christian Horner stressed his team’s submission of its 2021 cap was below the $145m limit, and was confident it had complied fully with the financial regulations.

But speaking to Sky Sports F1 on the issue, Wolff said it was an “open secret” that one team had gone way over the budget cap.

“It’s funny Christian says that because it’s been weeks and months they’re being investigated, so maybe he doesn’t speak to his CFO,” Wolff said.

“As a matter of fact, we all of us have been investigated diligently. And as far as we understand, there’s a team in minor breach, which is more procedural, and another team that is fundamentally massively over and that is that is being still looked after.

“So that’s an open secret in the paddock.”

Wolff called on the FIA to take severe action on the matter as Mercedes had sacrificed car performance, and made more than 40 staff redundant, to ensure it met last year’s cost cap.

“It’s heavyweight, it massively heavyweight,” he said. “We’re using used parts. We are not running what we would want to run, we are not developing what we could be developing.

“We have made more than 40 people redundant that are dearly missed in our organisation, and it was a huge mammoth project to make the cap.

“I don’t know how many tens of millions we had to restructure and reprocess in order to be below the cap. And if someone has been not doing that, or pushing the boundaries, every million [you don’t spend] is a massive disadvantage.”

The FIA is due to issue every teams compliance certificates next week, but while this relates to the 2021 season, Wolff fears that if Red Bull did overspend it could carry a performance advantage into 2023.

“The crucial part is that if you’ve been over in 2021, then you’ve been over in ’22,” Wolff said. “That means you have an advantage in ’23.

“If it’s true that they’ve [Red Bull] homologated the lightweight chassis this year, they may use it next year. So it’s a really a cascade of events that can be influential in all of the three championships.”