The European Union's injection of 70 million euros ($84 million) on Friday into the mission's operations helps bridge its shortfall of $135 million.
But the AU continues to struggle to run its peacekeeping operation in Sudan despite pledges made in May to give the mission an additional $200 million, Said Djinnit, the AU peace and security commissioner, said on Friday.
"As of today we have only resources in cash to maintain the mission to the end of March, very early April," Djinnit said.
"We are concerned about this because we have to maintain the mission and you have to have resources of you want to maintain the mission.
"The 7000-strong force needs $465 million (387.5 million euros) a year to operate, but so far they only received $330 million (275 million euros).
"In January important decisions should be taken in terms of providing resources to enable the mission to be maintained for the agreed timeframe or in terms of discussing other options."
On Thursday, an AU assessment mission, headed by Baba Gana Kingibe, the organisation's special envoy to Sudan, said that the presence of African Union troops in Darfur had helped reduce violations of a fragile ceasefire between the Sudanese government and rebels.
AU's special envoy says troops
have helped cut truce violations
The group, however, qualified that, saying the security situation did not allow for those made homeless or refugees by the conflict.
The UN estimates that 180,000 people have died, mainly through famine and disease, and several million more have either fled into neighbouring Chad or been displaced inside Sudan since the conflict began in February 2003.
That month two African rebel groups took up arms against the Sudanese government amid accusations of repression and unfair distribution of wealth.