McLaren and Force India have pulled out of next week's run-out in Bahrain to test next year's Pirelli tyres.
The governing body, the FIA, said on Monday that all six teams had accepted an invitation to test. But a Force India spokesman said: "The timescale was just too tight to make it, unfortunately." McLaren, 50 per cent owned by Bahrain's sovereign-wealth fund Mumtalakat, confirmed separately that they were not going either.
Pirelli said Ferrari, Mercedes, world champions Red Bull and sister team Toro Rosso would attend the session at the Sakhir circuit from 17 to 19 December to test the Italian supplier's tyres for next season. Pirelli had sought special permission to test to get as much feedback as possible on their planned 2014 tyres after having to revise this year's variants following a spate of blow-outs at the British Grand Prix in June.
The first regular pre-season test with all the teams present will be in Jerez, Spain at the end of next month.