Urban centers can be saved if there is strong federal and local leadership and if new initiatives are taken, Jay Janis, the new undersecretary of Housing and Urban Development, told the National Housing Conference this week in Miami.

Many cities are in difficulty today "largely because of a lack of a truly responsive and coordinated national urban policy," he told the housing group. Aside from its humanitarian aspects, action on urban problems is "good business," Janis said.

The previous administration, he contended, "had a different outlook on the cities of America."

He said there are signs that a number of cities, including the District of Columbia, are recovering from some of their problems. Washington, he said, has "made a comback. Old neighborhoods are blossoming under rehabilitation and revitalization. Middle-income families are moving back, and there is a fantastic boom in real estate."

He said that HUD Secretary Patricia Roberts Harris has convened a "working urban policy group" to work on some of the problems.

In an earlier speech here, Janis assured builders that HUD's main objectives include production of housing to meet the needs of low-moderate income Americans and slowing increases in the cost of housing.

One of the speakers at the housing forecast conference held by the National Association of Home Builders, the HUD official also said it is an administration policy aim to attract people back to central cities and to take care of low-income residents who now live there.

He added that financing of inner-city housing will aided by new leadership on the Federal Home Loan Bank Board and from the Federal National Mortgage Association.

Other speakers at the conference described the housing outlook as strong. Michael Sumichrast, chiec economist for the national homebuilder group, said housing starts this year will slightly exceed 18 million, including a record 1.4 million single-family units.