The 2017 sporting regulations state that no testing of current cars can take place on any track outside of Europe without the agreement of a majority of the teams and the governing FIA.
While Barcelona has been scheduled for the two four-day tests in February and March, that could change.
"(Tyre supplier) Pirelli have asked the FIA if they would support testing in Bahrain, which is outside Europe. So by regulation it requires a process to get there," Mercedes technical head Paddy Lowe told reporters at the Japanese Grand Prix on Friday.
He said Pirelli needed to test the new wider 2017 tyres in hot conditions and were concerned about what might happen otherwise.
"We’ve seen what can happen, for example, in Indianapolis 2005," said Lowe, referring to the infamous U.S. Grand Prix that saw only six Bridgestone-shod cars start after all the Michelin-provided teams withdrew on safety grounds.
"We need to run a 300 kilometres race with sensible numbers of tyres, so that’s not an inconsiderable risk and should be covered. So that’s why we particularly support that request," added the Briton.
Williams technical head Pat Symonds said he was firmly opposed.
"The cost of doing a test outside of Europe is vast," he told reporters.
"Depending on exactly how you do it and how much you have to ship back to the UK, how much you can ship on to the first race – we’re talking of a minimum of 300,000 pounds, probably a maximum of 500,000.
"A team like Mercedes, I’m sure that they can put contingencies in their budgets to cover things like that. A team like Williams simply can’t, it’s a significant amount of our budget."
Symonds said there was also the risk of sandstorms in Bahrain, and the first few hours can be spent clearing the track.
"I think Abu Dhabi would be a much better place, maybe even Malaysia. But as a team we’re opposed to the idea," he added.
(Reporting by Alan Baldwin in London, editing by Pritha Sarkar)
