Bill English isn't ruling out sending troops to Syria, should the US ask New Zealand for help toppling the Assad regime.
Friday's strike against an airfield with dozens of Tomahawk missiles has so far been a one-off, but it's sparked talk of World War III.
Newspapers across the world at the weekend published maps showing who's allied with who, and how a devastating global conflict might play out.
Mr English, speaking to The AM Show on Monday, said people were getting "a wee bit carried away".
"There isn't an indication this is going to unravel in that way… Both America and Russia have an interest in resolving issues in Syria without much broader disruption of further conflict."
The US called its strike a proportionate response to a chemical weapons attack on civilians, believed to have been carried out by Syrian government forces.
"If there was further chemical attacks, I would expect they would act again," said Mr English.
New Zealand, under Labour, declined to take part in the US-led invasion of Iraq in 2003 because it was conducted without approval from the United Nations.
Mr English says although it's unlikely the UN will back action against Syria because of Russia's veto at the Security Council, he's not ruling out New Zealand taking part.
"We much prefer to be inside the UN framework. The problem here has been that the Security Council hasn't been able to condemn the atrocities. We expect them to do that."
There has been no request from the US for New Zealand to take part yet.
"We'd be pretty cautious. There's been no request, we're not expecting a request. But if there was one, we'd consider it - but we'd be cautious," said Mr English.
"It's hard to see what the right answers are in Syria."