A U.N. expert in charge of freedom of expression, whose visit was postponed at the Foreign Ministry's request, will visit Japan in April, the ministry said Wednesday.

David Kaye, U.N. special rapporteur on the promotion and protection of the right to freedom of opinion and expression, will visit Japan from April 12 to 19 to conduct research on the situation over freedom of expression through meetings with government officials and nongovernmental organization, the ministry said.

His visit was previously scheduled for last December but the ministry made a request in November for rescheduling.

The request drew criticism at the time alleging that the government was seeking to hinder him from taking up such issues as the secrecy law for the prevention of leaks of state secrets.

Foreign Minister Fumio Kishida has said his ministry made the request as it cannot fully respond to his visit due to "budget compilation work."

Under the contentious secrecy law that took effect in 2014, civil servants or others who leak designated secrets will face up to 10 years in prison, and those who instigate leaks, including journalists, will be subject to a prison term of up to five years.