McLaren and Force India will not be attending Pirelli's Bahrain tyre test next week.
The governing body, the FIA, said that all six teams had accepted an invitation to test.
According to the Independent, a Force India spokesman said that the timescale was just too tight to make it, unfortunately.
McLaren, 50 percent owned by Bahrain's sovereign-wealth fund Mumtalakat, confirmed separately that they were not attending the test.