Warning that a new set of academic standards was on the verge of falling into the “dustbin of history,” the leader of a national teachers’ union called on Tuesday for school systems to postpone using new tests to evaluate teachers and promote students.

The leader, Randi Weingarten, president of the American Federation of Teachers, said teachers needed at least a year to master a new curriculum and review test materials before schools should be held accountable for results.

“Is this about deep learning or desperate cramming?” Ms. Weingarten said during an appearance in Midtown Manhattan, where she spoke before the Association for a Better New York, a group of civic and business leaders. “The only way this will succeed is if teachers have input and ownership.”

Ms. Weingarten’s message seemed aimed largely at New York, one of the first states in the nation to overhaul its tests in line with new standards, known as the Common Core. The tests made their debut this spring to the grumbles of many teachers, who said they had not been adequately trained to prepare students for the exam. Most states are not expected to adopt new tests until the 2014-15 school year.