McLaren is facing a race against time ahead of the 2019 Formula One season as plans to switch to Petrobras fuel and lubricants are not yet set in stone.
The team used BP/Castrol however had signed a deal last season to switch to Petrobras for the 2019 season however those plans look under threat ahead of winter testing.
Rumours from Brazilian media suggest that the company is set to be affected by a cut back on state-funded F1 spending which would impact McLaren's prospective partner.
Speaking at the launch of the MCL34, McLaren sporting director Gil de Ferran admitted that the situation was up in the air currently.
"I think we are still working on the development together with Petrobras. It would be difficult to put a timescale on it right now.
"When we make our plans we take all those difficulties into account, so we will make sure we execute them properly."
McLaren has experienced disastrous beginnings to a season in the recent past, their catastrophic partnership with Honda was marred with testing setbacks due to unreliability and the team is desperate for a clean beginning to 2019.
Although comparatively, the situation may not be as critical as with Honda, it is another setback that the team does not need as it looks to recover from a turbulent few years.