BEIJING (Reuters) - A murder suspect China wants extradited from New Zealand is "hyping up" his right to a fair trial so as to evade justice, China said on Tuesday, after a New Zealand court told the government to reconsider its decision to send the man back.

The case has thrown into sharp relief the hurdles China faces in its efforts to win international cooperation as it seeks to hunt down corruption suspects who have fled overseas.

Courts in China are not independent of the ruling Communist Party, and many Western nations have not signed extradition pacts with China over fears that the accused will be denied a fair trial or put to death.

In December, New Zealand agreed to extradite to Shanghai a South Korean-born resident, Kyung Yup Kim, but the Pacific country's High Court decided that China's assurances of fair treatment for the man were inadequate.

"Kyung Yup Kim and his lawyers have hyped up the issue of an impartial trial," Chinese Foreign Ministry spokesman Hong Lei told a regular news briefing. "In reality, it's for the purpose of evading legal sanctions."

China would continue to work with New Zealand authorities on the case, to "crack down on lawbreaking", Hong added.

Kim faced murder charges after the 2009 discovery in a Shanghai field of the body of a 20-year-old woman who had been strangled to death. He was put in prison after China sought his extradition in 2011, following his return to New Zealand.

China has faced criticism from human rights advocates for years for its heavy use of torture and the death penalty. Capital punishment is illegal in New Zealand.

In a court affidavit in February, New Zealand Justice Minister Amy Adams said the Chinese government had assured her Kim would get a fair trial and not face the death penalty.

China has pushed for an extradition treaty with New Zealand since 2014. In April, on a visit to Beijing, Prime Minister John Key said an extradition treaty with China was "possible", so long as people did not face torture or the death penalty.

(Reporting by Megha Rajagopalan; Editing by Clarence Fernandez)