Britain would back any United Nations-led military action taken to force out incumbent Ivory Coast President Laurent Gbagbo, William Hague has said.
But the UK's foreign secretary added this did not necessarily mean UK forces would be deployed there any time soon.
The international community has recognised Alassane Ouattara as the winner of the recent presidential vote.
The UK is also no longer recognising Mr Gbagbo's appointed ambassador to the country, Philippe Djangone-Bi.
West African leaders, under the auspices of the regional body Ecowas, have threatened to send in troops to remove him from power.
Mr Hague told BBC Radio 4's Today programme that the UK would, "in principle", support any move by the UN to authorise such action.
He said: "[The leaders] would be well advised to seek the authority of the United Nations to do that and we would be supportive of that at the UN."
But he added: "We are a long way here from discussing British forces being deployed.
"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."
Mr Hague said Mr Gbagbo must recognise the result of the election and urged him to step down.
He said: "Through all possible diplomatic means, we are supporting a resolution of this crisis."
Mr Ouattara and his cabinet are under the protection of UN soldiers at the Golf Hotel in Abidjan.
He was initially declared the winner of the elections, but his victory was overturned by the Constitutional Council.
Mr Gbagbo says his rival's victory was illegitimate and both men have been sworn in as president.
Ecowas is currently engaged with Mr Gbagbo in negotiations to resolve the crisis.
The presidents of Benin, Sierra Leone and Cape Verde left without a deal on Wednesday, but are expected to return on 3 January for more talks.
Nigeria's President Goodluck Jonathan, who is also the Ecowas chairman, is due to travel to Benin for talks on Friday with President Boni Yayi about the crisis.
The World Bank has said it has frozen financing for Ivory Coast, and Mr Hague added: "[Mr Gbagbo] will run out of money. His power relies on control of the army.
"He will run out of money in the next few weeks and that means his power will come to an end.
"He should not underestimate the determination of the international community that the will of the people of that country should be recognised."
The UK's Foreign Office (FCO) has informed Mr Djangone-Bi of the decision to no longer provide him with official recognition of the post given to him by Mr Gbagbo.
It said it will move to recognise the appointee of Mr Ouattara in the usual manner.
BBC correspondent Mike Woolridge said that Britain's move was in line with a decision of the EU Council earlier this month to accept the ambassadorial appointments of Mr Ouattara in EU capitals.
Meanwhile, UN chief Ban Ki-moon has warned Mr Gbagbo's supporters not to follow a call to storm the hotel where Mr Ouattara is staying.
A statement from his office said: "Any attack on the Golf Hotel could provoke widespread violence that could reignite civil war."
He said that an attack on peacekeepers constituted a crime under international law and its instigators would be held accountable.
The UN has some 9,500 peacekeepers in the country.
Mr Gbagbo has told them to leave, accusing them of interfering in Ivorian affairs, but the UN has refused to do so.
The former colonial power France has renewed a warning to its citizens in Ivory Coast to leave the country.
"Although foreign nationals are not at present threatened, the French authorities renew their advice... to all French who can, in particular families with children, to temporarily leave Ivory Coast," AFP news agency quotes the French foreign ministry as saying.
An estimated 14,000 French citizens live in the former French colony.
Almost 20,000 people - mostly women and children - have fled Ivory Coast for neighbouring Liberia since the impasse began at the end of November, fearing further unrest.