The Supreme Court of Gambia cannot rule on President Yahya Jammeh's challenge against his electoral defeat until May, according to its chief justice.
The ruling casts further doubt on whether a peaceful political transition will happen next week as scheduled.
The West African country has been thrust into a political crisis following a December 1 presidential vote, which saw longtime ruler Jammeh losing to opposition leader Adama Barrow.
Jammeh initially conceded defeat but later reversed his position, lodging a legal case aimed at annulling the result and triggering new elections.
Barrow, a former real estate agent, is scheduled to take office on January 19.
The election challenge was supposed to be heard on Tuesday by five judges, including Chief Justice Emmanuel Fagbele, but the Nigerian and Serra Leonean judges were absent.
Fagbele told Jammeh's lawyers that he needed a full panel to hear the petition but the outsourced judges would not travel there until either May or November.
The Gambia relies on foreign judges to staff its courts due to a lack of trained professionals in the tiny country.
The legal case was adjourned to Monday but Fagbele warned the petitioners that they should not expect anything different.
"We can only hear this matter when we have a full bench of the Supreme Court," Fagbele said.
His comments came as leaders from West African regional bloc ECOWAS pushed back from Wednesday to Friday a mediation mission in Banjul, the capital of Gambia.
Nigeria said the delay was at the "insistence" of Jammeh.

'Significant incentive'

Maggie Dwyer, from the Centre of African Studies at the University of Edinburgh, said the postponement of the election challenge "buys Jammeh more time and places the pressure on ECOWAS to broker a deal".
Speaking to News Agency, she said: "Without a significant deal reached, which would probably include amnesty for Jammeh and possibly senior military officers, it is very unlikely that there will be any transition next week.
"Jammeh will need a significant incentive and a way to save face in order for him to voluntarily leave office."
The court's announcement comes a day after Sheriff Bojang, the communications minister, stepped down and fled the country.
Bojang said he resigned because Jammeh's refusal to accept the outcome of the election was disregarding the will of the people.
Dwyer said defections by officials such as Bojang indicate that Jammeh is "becoming increasingly isolated" amid mounting pressure.
"Nearly all prominent organisations in the Gambia and the UN, AU, ECOWAS, US and more are unlikely to back down on their calls for Jammeh to concede defeat," she told Our Sources.