Argentine police say a cemetery watchman wielding a machete has killed his ex-wife, three of his children and a neighbor before hanging himself.

Prosecutor Mirta Ciancio says the attacker's brother in law reported that Roberto Vecino argued with his ex-wife Marta Esther Curutchet before attacking her at her home in the beach city of Necochea. He then killed daughters aged 22 and 19 and a 24-year-old son who had tried to flee.

A neighbor came to help, and also was slain.

Ciancio says Vecino also wounded a police officer before fleeting to a shed and hanging himself.

The motive for the attack was not immediately clear, though daughter Daniela Vecino told the C5N cable TV station that her father often beat his wife and children.