Venezuela blamed US sanctions for the non-payment of its United Nations fees, in a letter to the Secretary-General made public on Monday.
The outstanding debt has since January prevented Caracas from voting at the world body.
Last week, it was the only one of the UN's 193 members not to be allowed to vote for the new head of the General Assembly or in elections for the five new non-permanent members of the Security Council for the year 2021-22.
Caracas owes the United Nations tens of millions of dollars for its operating budget and for its peacekeeping operations.
US sanctions "have prevented us from transferring the funds to UN bank accounts located not just in the United States but in other countries too," said the letter from Venezuela's UN ambassador, Samuel Moncada, dated June 15 and addressed to Secretary-General Antonio Guterres.
"Each time we have tried to make an electronic transfer, the transactions have been rejected and, in the best case scenarios, returned to our accounts," it added.
At other times, the Venezuelan ambassador said, the funds had been "frozen or confiscated."
Venezuela "has always had both the political will and the financial capacity to pay, on time, its dues to the organization," the letter said.
It called on Guterres to "find and establish a financial route" that would allow Venezuela to meet its obligations.
To regain its voting rights, Venezuela will have to come up with almost $22 million in unpaid dues.
"We have sufficient financial resources to meet our obligations to the UN," Moncada said.
The United Nations logo is seen at the United Nations Headquarters in New York: Venezuela has blamed US sanctions for its debt to the world body