The government is considering postponing the implementation of parts of a labor reform bill for a year after acknowledging fundamental flaws in its work hours survey, sources close to the matter said Wednesday.

Opposition parties have accused the government of deliberately designing the survey to make it look like expanding the "discretionary labor" system would help lessen Japan's chronic overwork problem. They argue it could have the opposite effect.

Prime Minister Shinzo Abe has apologized for citing the erroneous survey in Diet debate.