The companies had already parted in terms of their joint road sports car programmes, and reports have intensified throughout this week that a similar split is looming in terms of their 15-year F1 collaboration.
On Wednesday, the German magazine Auto Motor und Sport claimed that McLaren is getting in the way of Mercedes' plans for 2010 by currently vetoing the intended engine supply deal with Red Bull Racing.
The tension on this front is almost certainly also linked with yet another team, as both the German language Blick and Auto Motor und Sport publications report that Brackley-based Brawn GP is set to be 75 per cent owned by Mercedes by 2012.
McLaren has a contract for exclusive works rights until the end of 2011, so until Mercedes can buy Brawn itself, the Daimler AG shareholder AABAR of Abu Dhabi could hold the stake, Auto Motor und Sport said on Thursday.
"If we wanted to change anything with our formula one commitment then we could certainly speak with Abu Dhabi," Mercedes parent Daimler CEO Dieter Zetsche is quoted as saying.
Auto Motor und Sport said contracts with Brawn GP are to be signed shortly, with a deal to include a silver livery from 2010 and the Mercedes logo on the engine cover.
Brawn's new title sponsor is said to be a German company, and 24-year-old German Nico Rosberg is the favourite to become Jenson Button's 2010 teammate, the report added.