* Foreign exchange reserves drying up
* Imports, investor confidence eroded
JUBA, Sudan, (Reuters) - South Sudan said on Monday that the central government had stopped paying its share of oil revenues in foreign currency, creating a foreign exchange crisis in the region ahead of a January vote on independence.
Under a 2005 north-south peace deal which ended a two-decade long civil war, the south receives about 50 percent of Sudan's oil revenues. The oilfields are in the south but all the ports and refineries are in the north, so wealth-sharing is likely to continue even if the south votes to secede on Jan. 9.
The semi-autonomous South Sudan government derives some 98 percent of its budget from oil revenues, making its economy almost totally dependent on the cash sent from the north.
David Deng Athorbei, the south's finance minister, said the decision to pay its oil revenues in local Sudanese pounds since July was a "sinister" ploy to unsettle the south's economy.
"This is a clear attempt to violate the CPA (peace accord)," Athorbei said. "It is an attempt by NCP (the north's ruling party) to stifle the southern Sudanese economy."
He said the north had taken similar action in June 2008, but the dispute had been resolved through political dialogue.
The finance ministry in Khartoum was not immediately available to comment, but the Central Bank has suffered a massive depletion in foreign currency over the past year because of the global financial crisis.
Athorbei said the switch to local currency payments meant the south's central bank was unable to supply southern banks and foreign exchange bureaux.
"Investor confidence in southern Sudan is eroded," he said. "(It) is starving the economy of southern Sudan of the hard currency it needs to operate."
Athorbei said the Sudanese pound had fallen sharply against the dollar since the change, dropping to 3.10 to the dollar in the south compared with the national exchange rate of 2.43.
"If the situation is not reversed it means southern Sudan cannot import essential commodities which are necessary for our development, like steel and cement," he said.
Most of Sudan's oil lies near a disputed north-south border and the parties are negotiating the future shareout of oil revenue. The fact that both sides rely on oil revenue gives them an interest in ensuring that a southern secession would be carried out amicably.
But failure to agree on post-secession wealth-sharing could also lead to conflict.
(Editing by Opheera McDoom and Tim Pearce)