Gordon Brown is planning to organise the meeting in December 2008 to discuss improving dialogue between oil consumers and producers
The event is a follow-up to a meeting of major producers, consumers and top oil company executives held in Saudi Arabia's commercial capital Jeddah in June in an attempt to rein in soaring oil prices.
UK officials would not give the date of the meeting but an Opec delegate in Vienna said it is likely to be around 19 December, two days after an Opec meeting in Algeria.
Brown's spokesman would not confirm or deny a report in the Financial Times that Brown would send invitations to Libyan leader Muammar Gaddafi and Venezuelan President Hugo Chavez.
The report said Brown was highly unlikely to invite Iranian President Mahmoud Ahmadinejad, who has been at odds with the West over Iran's nuclear programme.
By the way, invited countries could choose to be represented at different levels at the London meeting, such as head of state or oil minister.
The main task of the London meeting is to "take forward the very constructive discussions at Jeddah" aimed at enhancing dialogue between producer and consumer countries.