U.S. gross domestic product growth is likely to resume in the second half of this year but the U.S. labor market should lag any such improvement, the president of the Federal Reserve Bank of Boston said on Monday.

"GDP is expected to start being positive in the second half of this year, the unemployment rate is likely to lag, so that the peak in the unemployment rate is likely to be sometime early next year," Eric Rosengren told reporters on the sidelines of an economic conference in Brussels.