Taipei, Dec 28 (DPA) An 83-year old man in Taiwan has admitted murdering his wife with a screwdriver in what he claims was a "mercy killing" in the light of her Parkinson's disease.

Wang Ching-hsi, a retired engineer, killed his wife Sun Yuan-ping, 80, who suffered from Parkinson's' disease, at their Taipei home Sunday.

Wang gave her sleeping pills then used a hammer to knock the screwdriver in her skull. Wang then turned himself in to police, claiming he performed euthanasia to end her suffering.

Wang said his two sons emigrated to the US, and he has been caring for his wife who had a broken leg in addition to Parkinson's disease.

Not wanting to face old age and illness, they discussed committing suicide a decade ago, and he mentioned it several times in his blog.

"We have lived enough. We discussed it a decade ago. If she died before me, it would be her good luck. If necessary, I would punch a hole in her head with an electric saw," he wrote Dec 1.

Wang has been charged with murder and prosecutors plan to perform a post-mortem to determine the cause of Sun Yuan-ping's death.

Euthanasia is still illegal in Taiwan, but the island in June passed draft regulations allowing family members to suspend medical efforts that prolong suffering without preventing eventual death.