David Miliband has urged feuding Kenyan leaders to reach an arrangement on power-sharing to end the violence gripping the country.
As many as 350 people are believed to have died following the eruption of fighting after elections were disputed.
The foreign secretary has called on president Mwai Kibaki and opposition leader Raila Odinga to come to an arrangement to end the violence.
"Serious questions about the conduct of the count stand in the way of the formation of a stable Kenyan government that commands the confidence of the Kenyan people and is able to unite the country," he said.
"It is vital that the democratic process works and is seen to work."
Mr Miliband said he would give parliament an update on the situation upon Westminster's return following the Christmas recess but said the coming together of the disputing parties was the key to progress.
"The message to Kenya's political leaders is therefore clear: the basis for the country to move forward is political compromise which recognises the divided nature of the electoral vote and establishes a basis for politicians of different parties to work together in a way that reflects the will of the Kenyan people," he added.
"The sharing of political power is the way to build bridges across serious divides."
Mr Miliband's comments come as US assistant secretary of state Jendayi Frazer visits Nairobi to hold talks with both sides.
Her visit occurs as the United Nations issued a warning that as many as 500,000 Kenyans have been displaced by the conflict and are in further danger.