MONZA, Italy, Sept 4 (Reuters) - Double Formula One world champion Lewis Hamilton has warned his employers Mercedes that it would be a mistake to supply rivals Red Bull with engines if that team's partnership with Renault comes to an end.
The possibility has been mooted should Renault withdraw from the sport or acquire Lotus as their favoured works team.
The French manufacturer is currently assessing its options, with a decision expected soon.
"I think if we're serious about winning world championships, probably not," Hamilton told Sky television at the Italian Grand Prix when asked whether it would be a wise move for Mercedes, whose power unit is currently dominant.
"Red Bull is a great team and it's like giving Ferrari our engine," added the Briton, 28 points clear in the championship and well on the way to a third title.
"We're here to win so we don't really need it. There's no financial benefit really in it, so I think we're good where we are."
Mercedes motorsport head Toto Wolff was more pragmatic.
"From a team perspective you have to have a no-prisoners approach and look in an opportunistic approach," said the Austrian. "But it's also a matter of what we can do to make F1 function."
The Williams team, who have Mercedes engines and are currently third and ahead of Red Bull in the championship, also voiced understandable opposition to any deal that gave their nearest and better-funded rivals an advantage.
"How do I feel about it? Not great, to be honest," said deputy principal Claire Williams when asked about the prospect. "it doesn't fill me with much joy.
"At the moment obviously we are ahead of Red Bull but Red Bull are never going to be down for too long and we need to make sure if they do get an engine, then fair enough and we have to deal with it.
"But that is a conversation between Red Bull and Mercedes that we have no influence on whatsoever. We therefore will just have to produce a better chassis...I don't believe a Red Bull powered by Mercedes would absolutely jump ahead of us."
Williams said they had no preferential terms with Mercedes, who treated all their customer teams with parity. (Reporting by Alan Baldwin, editing by Justin Palmer)