Yes, if a treaty explicitly permits it, as does for example article 52 of the International Convention on Children Rights. However, the International Covenant on Civil and Political Rights (ICCPR), its Second Optional Protocol, the International Covenant on Economic, Social and Cultural Rights, the Convention on the Elimination of all Forms of Discrimination against Women and the International Convention Disappearance do not permit a denunciation of the treaty. Regarding the ICCPR, this was confirmed by the Human Rights Committee in its General Comment No. 26 on the continuity of obligations from 1997. Before, the committee had already declined North Korea’s denunciation and Jamaica’s denunciation from the Second Optional Protocol to the ICCPR.
When a state finds itself in a state of emergency, some civil-political human rights may be temporarily restricted (“derogation”, Article 4, ICCPR). However, a state of emergency always has to be officially declared and accounted for, and has to be limited in time. Some human rights like the prohibition of torture cannot be derogated under any circumstances. All other human rights treaties do not allow the temporary derogation of particular rights in a state of emergency.
Deutsche Geschellschaft für Internationale Zusammenarbeit (GIZ) (2013): Promising Practices - On a human rights-based approach in German development cooperation. GIZ, 26 p.
Deutsche Geschellschaft für Internationale Zusammenarbeit (GIZ) (2011): National Human Rights Institutions. GIZ, 10 p.