Former Rep. James F. Hastings (R-N.Y.) was sentenced yesterday to a prison term of 20 months to five years on his conviction of forcing two of his congressional employees to pay him kickbacks.

U.S. District Court Judge June L. Green said she was imposing the sentence - believed to be the stiffest in at least a decase to be imposed on a current or former congressman - to "put on notice those few (public officials) whose actions do violate the law."

"You were elected to a position of honor with grave national responsibilities," Green told the ex-congressman. "The conduct for which you have been found guilty constituted a violation of that public trust.

"The allegations that you action in receiving kickbacks was standards procedure denigrates the vast majority of honorable public officials," Green added.

The judge said she had received letters from Hastings' former consitutents to the effect that Hastings had served his Western New York district well, that he and his family had suffered enough already and "that since everybody does it, it is unfair to make an example of you." She made her statements at sentencing in reaction to those letters, she indicted.

Hastings' attorney, Jacob Stein, said his client had decided no to appeal the jury verdict that convicted him of 28 counts of mail fraud and other charges last month.

Hastings was given one week to get his affairs in order before reporting to a prison to be designated by the Federal Bureau of Prisons.

A grand jury had charged that Hastings had earned more than $40,000 over a seven-year period by giving his employees raises or salaries that they had to kick back directly to him.

Hastings, who resigned from Congress last January to take a higher-paying job as a lobbyist in New York State, used the illegally obtained money to buy cars and snowmobiles and to pay his children's college tuition, investigators said.

Hastings said yesterday that he had done a "great deal of soul searching" since his conviction, and asked the judge to "view the entire structure of my life."

"View my productive life," Hastings said. "View the success I have achieved."

Hastings, the 50-year-old father of five children, was a congressman for seven years before resigning to become president of Associated Industries of New York. At the time of his retirement, he said he had accumulated a large debt.