RALEIGH – The chief regulator of mortgage buyers Fannie Mae and Freddie Mac says restructuring the country’s housing finance system may require more mortgage insurance and charging lenders more, steps that could increase borrowing costs.

Federal Housing Finance Agency acting director Edward DeMarco said Monday at a conference in Raleigh that reshaping the mortgage giants three years after the federal government took over them over involves spreading risks.

DeMarco says reducing the risk to taxpayers may mean private interests take on more risk, perhaps by requiring more private mortgage insurance from borrowers and higher fees from lenders to guarantee loans.

DeMarco says the most pressing tasks include creating a framework allowing more borrowers who are underwater on their mortgages to refinance now at rates that are at levels not seen in decades.