Kadyrov, a former rebel, also stayed away from the widely-advertised conference, which was attended by a handful of local officials and low-key Chechen rights defenders.
The only figure of international status attending it was Thomas Hammarberg, the European commissioner for human rights.
In Chechnya on a fact-finding mission, Hammarberg accused its leadership this week of using systematic torture in prisons.
Other participants included Ella Pamfilova, chair of Russian President Vladimir Putin's human rights advisory council, and Kadyrov aides.
Two dozen Chechen women rallied holding pictures of their missing sons outside the new finance building in the capital Grozny, where the conference was held.
"Please help us find our sons and return them to us. We don't know what to do," one woman asked reporters.
Rights activists say hostage-takings by security forces are widespread in Chechnya, while torture is systematic.
Arbitrary charges are regularly brought against innocent civilians, activists say.
They accuse Kadyrov's men of using illegal arrests and torture. Kadyrov, promoted by Putin to acting president this month, denies the charges.
Svetlana Gannushkina, a leading Russian rights activist, and Memorial rights group said they did not attend the conference.
"Politics should not be mixed with human rights," Gannushkina said.
"We should first understand how to work with Kadyrov and only then hold human rights conferences."