TOKYO (AP) -- A United Nations expert who investigated the aftermath of Japan's 2011 nuclear power plant disaster says the government and the operator of the facility should do more to help those affected by the catastrophe.

A report by special rapporteur Anand Grover, posted on the U.N. Human Rights Council's website, says the government's takeover of Tokyo Electric Power Co. allowed the utility to evade full responsibility for the nuclear disaster, the worst since Chernobyl.

The report points to problems with the handling of the crisis, including a difficult process for seeking compensation for radiation exposure, a lack of openness about health risks from radiation and inadequate protection for nuclear plant workers.

It urges Japan to improve its emergency preparedness and its handling of compensation claims.