* Western diplomats worry UN summit will blast capitalism

* General Assembly chief's spokesman says charge is unfair

By Louis Charbonneau

UNITED NATIONS, June 9 (Reuters) - Western diplomats are accusing the leftist former Nicaraguan foreign minister who heads the U.N. General Assembly of hijacking an upcoming U.N. summit on the financial crisis to put capitalism on trial, an allegation his spokesman on Tuesday flatly rejected.

Diplomats from the so-called Group of 20 large developed and developing economies criticized U.N. General Assembly President Miguel D'Escoto Brockmann and called the June 24-26 summit a "joke," a "tragedy" and a "waste of time."

The five G20 diplomats who spoke to Reuters about the summit all declined to be quoted by name. They said the U.N. meeting, which is supposed to focus on the impact the financial crisis has had on the developing world, would instead be used as a platform for speakers who want to attack capitalism.

D'Escoto's spokesman Enrique Yeves rejected this, saying, "These criticisms are not justified, they are not fair."

In a recent interview with Britain's Financial Times newspaper, D'Escoto accused industrialized states of attempting to sabotage the summit and said the British Foreign Office was trying to divide him and his advisers, one of whom is Joseph Stiglitz, the Nobel prize-winning economist.

D'Escoto, who is expected to be succeeded in the largely ceremonial U.N. post by former Libyan foreign minister Ali Triki in September, has managed to annoy many Western delegations since taking office last year.