Britain said on Friday it would give support at the United Nations for the use of force to oust Ivory Coast's Laurent Gbagbo if West African nations sought backing for a military intervention.
British Foreign Secretary William Hague said the support would not include the deployment of UK troops.
World leaders have stepped up pressure on Gbagbo to quit in favour of challenger Alassane Ouattara, who is widely recognized as having won the presidential election on 28 November.
"(Gbagbo) should not underestimate the determination of the international community that the will of the people of that country should be recognised and a democratic transfer of power take place," Hague told BBC radio.
West African regional bloc ECOWAS has threatened to use force to oust Gbagbo if he does not leave quietly.
Asked if Britain would support a military intervention by ECOWAS, Hague said: "Yes, in principle ... They would be well advised to seek the authority of the United Nations to do that. But we would be supportive of that at the United Nations."
But he played down the prospect of direct British military intervention.
"There are U.N. peacekeepers in Cote d'Ivoire, there are large numbers of French forces there," he added. "We have deployed a military liaison officer to the country to work on various contingencies with the French, but I'm not raising the possibility today of British forces being deployed."
Three West African leaders will return to Ivory Coast next week to try to persuade Gbagbo to stand down.
The dispute over the election results has provoked lethal street clashes and threatens to restart open conflict.
The United States and European Union have imposed sanctions on Gbagbo and his inner circle, while the World Bank and the West African regional central bank have cut his financing.