The trustees of the New York state teacher retirement system yesterday disputed a contention by union officials that their withdrawal of pension funds from Manufacturers Hanover Trust Co. was connected with an Arizona copper strike.

Albert Shanker, president of the 600,000-member American Federation of Teachers, said at a Florida AFL-CIO press conference Tuesday that New York and Pennsylvania teacher retirement systems had withdrawn $450 million and $300 million, respectively, in pension funds in the last month because of the bank's "poor performance."

But Shanker also said an "obvious concern" underlying the decision was the bank's financial backing of Phelps Dodge Corp., the target of a bitter, sometimes violent, strike since July 1983.

"Our removal of money had nothing to do with the Phelps Dodge incident" and was actually part of a year-old program to "diversify" pension investments by withdrawing more than $2 billion from the bank, a spokesman for the New York system said. A Manufacturers Hanover spokesman said Shanker had "spun a tale" and that withdrawal of the Pennsylvania pension funds from a public employe system had occurred more than a year ago, before unions even began a campaign against Phelps Dodge.

The AFT yesterday "clarified" Shanker's statement, saying that the New York withdrawal was actually $200 million and acknowledging that the Pennsylvania withdrawal occurred a year ago.