Uganda's rebels are demanding $2m from donors, or they say they will not return to peace talks in South Sudan.
Thousands still live in displaced camps
Lord's Resistance Army (LRA) technical adviser David Nyekorach told the BBC the money was needed for consultations with its various groups.
Talks between the Ugandan government and the LRA rebels were expected to resume this week.
Some 2m people have fled their homes and thousands of children have been abducted during the 20-year conflict
In January, the LRA refused to resume talks after Sudan's president accused them of committing atrocities in South Sudan and threatened to evict them.
They however returned following a meeting between UN peace envoy Joachim Chissano and LRA leader Joseph Kony.
Mr Nyekorach said their technical team has been unable to travel to the affected areas to solicit the views of its people due to lack of funding.
"The talks are on course but we cannot return to the table without suggestions from the people, so this money is important," Mr Nyekorach told the BBC.
He said donors had failed to pay the money they had promised.
Uganda's government has also indicated that it is not ready to resume talks aimed at achieving peace in the north of the country.
Mr Nyekorach said they hope that the funding would be released to enable the peace talks to resume at the end of August.
LRA leader Joseph Kony and three of his top commanders are wanted for war crimes at the International Criminal Court and have indicated that no deal will be signed while the warrants for their arrest are still in place.
But last month, the two sides agreed to use Ugandan justice to address human rights abuses.