Millions of Americans began earning larger paychecks Monday as the federal minimum wage jumped by 45 cents an hour to $4.25, but organized labor says it falls well short of lifting many workers out of poverty.

"They can't support a family on this and in many cases can't support themselves," said Rudy Oswald, chief economist of the AFL-CIO, which wants the base wage increased to $5.75 an hour by April 1994.The increase in the minimum wage from $3.80 an hour is the second step of a two-part increase Congress enacted in 1989 after a long and fierce battle with the White House. President Bush had vetoed an earlier version he considered too hard on businesses.

The first step of the increase took effect a year ago, when the minimum wage went from $3.35 an hour to $3.80. It was the first increase in nearly a decade.

About 3 million Americans earn the minimum wage. But millions of higher-paid workers also may benefit because the boost could put pressure on employers to boost their wages by comparable amounts.

Sen. Edward M. Kennedy, D-Mass., chairman of the Senate Labor and Human Resources Committee, called the 45-cent raise an "April Fools' increase, well below what low-wage workers deserve. Just to restore the ground lost in the Reagan years, the minimum should be $5.15 an hour today," Kennedy said.

Business executives dismissed the need for another boost, and the White House indicated it probably would oppose another increase.

"I don't know what kind of dream world they're in," John Meritt, a senior vice president of Hardee's restaurants, said of the advocates of another increase. "When (the cost of) your labor component goes up, it ultimately gets passed on to the consumer," Meritt said.