A Malaysian prince stabbed his mother to death with a "Rambo knife" and a screwdriver and seriously wounded his father before dying of a suspected drugs overdose, police said today.

Tunku Shahzan, 21, slashed his 64-year-old mother Tengku Putri Kamariah Sultan Abu Bakar in the back as she tried to protect her husband, police in Malaysia's eastern Pahang state told AFP .

The prince died later at a hospital in the state capital Kuantan, a police spokesman said. "He may have died of a drug overdose, but we cannot speculate until the post-mortem results are out," he said.

His father Tunku Ismail Tunku Sulaiman, 69, is in stable condition after undergoing surgery at the same hospital.

"Before he was rushed to hospital he already knew that his wife had died but he still doesn't know that his son is dead," the police spokesman said.

The dead woman was the half-sister of the Sultan of Malaysia's eastern Pahang state.

Newspaper pictures showed Sultan Ahmad Shah staring at her corpse, which was covered with a sheet. They also showed the bloodied murder weapon.

Motive under probe

Police are currently investigating the motive but said they suspected Tunku Shahzan was under the influence of "some kind of designer drugs".

A relative who lives next door to the royal family told the Star newspaper that he tackled the killer prince after he climbed into his compound.

"He looked strange, and his eyes were red and bulging," Tengku Ahmad Faisal said.

He said he then tried to help Tunku's mother who was bleeding to death in the kitchen. "She was very weak... She died in my arms," he said.

Pahang is the largest state in peninsular Malaysia and is situated in the eastern coastal region.

Each of Malaysia's states has its own royal family. Under the country's unique revolving monarchy, the nine state sultans take five-year turns in the largely ceremonial role.