The UK and France will hold the first virtual meeting of defence ministers from over 40 countries today.
The forum aims to coordinate an international defence mission to protect shipping in the Strait of Hormuz.
Passage through the strategic corridor has been severely restricted since the outbreak of war between the US, Israel and Iran in late February.
British Defence Secretary John Healey and his French counterpart Catherine Vautrin are co-chairing the event.
The countries will discuss specific military contributions to mine clearance, escorting merchant ships and providing air support.
London and Paris stress that the plans are purely defensive in nature. The aim is to restore global supply chains and contain rising oil prices.
Ahead of the meeting, Britain sent the destroyer HMS Dragon to the region, and France positioned the aircraft carrier Charles de Gaulle.
Iran issued an official warning to London and Paris, saying that sending foreign warships would be met with an “immediate and decisive response“.
Tehran insists that only Iran can guarantee security in the strait.
In response, French President Emmanuel Macron clarified that the mission would be coordinated with Iran and that France was not planning offensive operations.