The Carter administration has come up with a new plan to find permanent private-sector jobs for the nation's hard-core unemployment.

The plan, revealed at a news conference yesterday, attempts to use the carrot-and-stick approach -- without any formal means of enforcement -- to win the cooperation of private-sector employers seeking nearl $2 billion in available federal economic development money.

Under the proposal, applicants for the assorted development grants are encouraged to set aside some of the "permanent" private sector jobs generated by their projects for hard-core unemployed persons living in the project areas.

The key word is "encouraged" because "it's not an absolute condition for the applicant to promise to take in" eligible unemployed persons for permanent jobs, according to Bruce Kirschenbaum, an associate assistant to the president for intergrovernment affairs.

Nor are there any formal penalties for successful development grant applicants who might renege on promises to privide permanent jobs to the long-term umemployed, Kirschenbaum said.

There simply is an understanding that a grant application with a permanent-job prvision has a better chance of being approved than one without such a provision. It also is understood generally in the national grantsmanship community that applicants who renege on promises are not re-funded, Krischenbaum said.

"People know what has to do done," he said.