Ivory Coast must resolve its political crisis soon or face being frozen out of aid deals, say international lenders.
The World Bank and African Development Bank say they will review their ties with the country following the "breakdown in governance".
The EU has warned the crisis threatens regional stability and has hinted that economic sanctions could be imposed.
A disputed election has left the country with two presidents, who have begun naming separate cabinets.
Western nations have thrown their support behind Alassane Ouattara, who was standing as an opposition candidate in the 28 November poll.
Initial results from election officials gave him a clear victory over incumbent Laurent Gbagbo.
But the result was overturned by the Constitutional Council, and Mr Gbagbo insists he won.
In a joint statement, the development banks, which invest millions in projects designed to alleviate poverty, urged the politicians to break the impasse.
"We wish to continue working with the people of Ivory Coast in the fight against poverty but it is difficult to do so effectively in an environment of prolonged uncertainty and tension," they said.
"We will continue to closely monitor developments and reassess the usefulness and effectiveness of our programmes given the breakdown in governance".
Former South African President Thabo Mbeki is mediating in the crisis, which has sparked concern across the world.
On Monday, European Commission president Jose Manuel Barroso said the crisis risked stability and peace in the country and the region.
A spokeswoman for the EU's foreign policy chief, Catherine Ashton, said sanctions could be imposed if no solution was found. BBC News
