Foreign Secretary Jeremy Hunt on Monday said Britain wanted to establish a European-led maritime protection force in the Gulf but emphasised that London was not seeking a confrontation with Iran.
"We will now seek to put together a European-led maritime protection mission to support the safe passage of both crew and cargo in this vital region," Hunt told parliament after Iranian authorities seized a British-flagged tanker in the Gulf on Friday.
"We will seek to establish this mission as quickly as possible," he said, adding: "It will not be part of the US maximum pressure policy on Iran".
Hunt described Friday's incident as an act of "state piracy".
A British warship in the region, HMS Montrose, attempted to warn off Iranian forces and raced to the scene but arrived too late to be able to assist.
Hunt said a second British warship, HMS Duncan, that is being dispatched to the region, would arrive by July 29.
Hunt said all British-flagged ships would be asked to give the British authorities notice when they plan to pass through the Strait of Hormuz, where Friday's incident happened, "to enable us to offer the best protection we can".
But he added: "It is, of course, not possible for the Royal Navy to provide escorts for every single ship or indeed eliminate all risks of piracy."