A United Nations envoy on human rights, Soli Sorabjee, has said at the end of a visit to Nigeria that there's been a noticeable improvement since the death of the last military ruler, General Abacha.

Mr Sorabjee said the Nigerian government was now willing to accept criticism, and he had no doubt it wanted to return the country to civilian rule.

However, he stressed that several decrees needed repealing, including one on detention without trial, and he said prison conditions were terrible.

Mr Sorabjee's remarks came as Nigeria prepares for local elections on Saturday -- the first in a series of polls leading to a planned civilian handover next May.