Japan's current economic expansion has become its second-longest in the postwar era, a government panel concluded Thursday, surpassing the 57-month boom between 1965 and 1970.

The panel, which determines the length of periods of economic strength retrospectively, endorsed the view among government officials and economists that the expansion phase from December 2012 under Prime Minister Shinzo Abe entered its 58th month in September last year.

The assessment bolsters the likelihood of the current growth phase in January 2019 becoming the longest in the postwar period, amid criticism that consumers have yet to fully feel its benefits as wage growth remains modest.