* Nicaragua says to help Libya after a visa ban
* Nicaragua names diplomatic critical of U.S.
MANAGUA, March 29 (Reuters) - A former Nicaraguan leftist foreign minister who has been a sharp critic of U.S. governments will represent Libya at the United Nations after its delegate was denied a visa, Nicaragua said on Tuesday.
As governments and international bodies agreed to press on with a NATO-led aerial bombardment of Libyan forces, Nicaragua said Miguel D'Escoto Brockmann, who once called former U.S. President Ronald Reagan "the butcher of my people," would replace senior Libyan diplomat Ali Abdussalam Treki.
The government of leftist President Daniel Ortega, a former U.S. Cold War foe who has forged ties with Libyan leader Muammar Gaddafi, said it had sent a letter to U.N. Secretary-General Ban Ki-moon to inform him of the decision.
The Nicaraguan government said in a statement that D'Escoto has flown to the U.N. headquarters in New York to "support our Libyan brothers in their diplomatic battle to enforce respect for its sovereignty."
Some Western media have reported that Gaddafi's children have urged the Libyan leader to seek exile in Nicaragua. Ortega said last month he telephoned Gaddafi several times to offer him support.
A former president of the U.N. General Assembly, D'Escoto was foreign minister in Ortega's Sandinista administration that ruled Nicaragua from 1979-90, during which time it fought against an insurgency by U.S.-backed Contra rebels. He was born in Los Angeles and ordained as a Roman Catholic priest. (Reporting by Ivan Castro; Editing by Bill Trott)