A United Nations committee has expressed regret over the lack of progress and efforts by Japan over its wartime sexual slavery, calling on Tokyo to offer a public apology and compensation for the victims.

The UN Committee of Civil and Political Rights made the call as it released recommendations and main concerns on Japan's implementation of the International Covenant on Civil and Political Rights.

In its review, the committee assessed that Japan has not made progress regarding the wartime sexual slavery issue.

The committee noted that the offenders responsible for the issue were not put to criminal court and there has been a lack of adequate reparations to the victims.

The committee said that Japan is rejecting its duty to deal with the ongoing violations of human rights of the victims, which is regrettable.

The committee called on Japan to conduct independent investigations of the wartime sex slavery, indict and punish those responsible, make judicial remedies available for the victims and make adequate compensations.