Vandals have attacked a site commemorating the murder of dozens of Aborigines in northern New South Wales.

The Myall Creek Massacre occurred in the 1830s near Inverell when white settlers killed dozens of Aboriginal men, women and children.

An act of reconciliation between the local Indigenous people and the wider community led to the construction of the memorial highlighting the slaughter.

Vandals have defaced a number of plaques at the site by trying to scratch out the words "murder, women and children".

While the plaques are replaceable, the attack has been condemned by local caretakers as racially motivated.

A police investigation is under way to find those responsible.