Senior south Sudanese politicians on Saturday accused government officials of withholding funding from the country's contested oil town of Abyei, stoking tensions and raising the risk of new violence.

Both north Sudan and the semi-autonomous south claim ownership of Abyei -- at stake is control over nearby oilfields and a key pipeline funnelling crude to Sudan's Red Sea coast.

The boundaries of the town and surrounding territory were left undecided in the 2005 Comprehensive Peace Agreement that ended more than two decades of north-south civil war.

Clashes between northern and southern Sudanese forces in May and December raised fears for the peace deal.

Southern leaders on Saturday said the Khartoum government had not sent money to support a new Abyei authority which is supposed to re-build the central town after it was burned to the ground in the May fighting.

"It is a deliberate intention to create despair in the people of Abyei," said south Sudan's Minister for Presidential Affairs Luka Biong. "That feeling (of despair) is developing and it is very alarming."

Biong told Reuters a 280 million Sudanese pound ($126 million) fund to establish the administration and rebuild the town had been passed by Sudan's national parliament and agreed by Sudan's President Omar Hassan al-Bashir.

But the transfer of the cash had been blocked by Khartoum's ministry of finance, he said.

Biong said it was unclear why the finance ministry had not followed through on the presidential orders.

Neither of the two main ethnic communities, the Ngok Dinka and the Arab Misseriya, have received a promised share of the region's oil revenues either, he added.

No one was immediately available for comment from the ministry of finance.

Pagan Amum, secretary general of the Sudan People's Liberation Movement (SPLM), the south's dominant party, told reporters in Khartoum he was planning to bring up the funding shortfall during meetings with northern officials next week.

"It is unacceptable. The (Abyei) administration up to now has no funds. We don't understand why this money has not been released by the ministry of finance," he said.

The leader of the new Abyei administration, Arop Moyak, said some key members of staff were considering leaving their jobs after receiving no pay.

"There are no services. People are getting fed up," he said.

Around two million lost their lives in Sudan's north-south war that also displaced another four million mostly southerners. South Sudan won its own semi-autonomous parliament and the promise of a vote on southern secession in 2011 under the peace deal that ended the conflict.