SEOUL, Sept 2 (Reuters) - North Korea's foreign ministry criticised a new United Nations human rights expert as "biased", saying the country will not tolerate what it called U.S.-led efforts to topple the isolated regime, state media KCNA reported on Friday.

Elizabeth Salmon, the new U.N. expert on human rights in North Korea, is on her first official visit to South Korea since taking office last month. In her inaugural statement, Salmon said the North's human rights situation has worsened following over two years of strict measures to curb COVID-19.

"We had already made clear our principled stand that we neither recognize nor deal with any 'special rapporteur' who is merely a puppet of the U.S.," KCNA cited an unidentified spokesperson of the Ministry of Foreign Affairs as saying.

Pyongyang has repeatedly rejected accusations of human rights abuses and criticised U.N. investigations into the matter as a U.S.-backed scheme to interfere with its internal affairs.

"The DPRK will never pardon the U.S. and its vassal forces' 'human rights' racket against the DPRK which is aimed at overthrowing its social system," the official said, referring to the North by its official name, the Democratic People's Republic of Korea (DPRK).

A separate recent U.N. report also said North Korea's coronavirus containment measures have exacerbated the country's human rights violations, citing extra restrictions on access to information, tighter border security and heightened digital surveillance.

Salmon was set to hold a news conference later on Friday.