Backpack belonging to 2003 murder victim reportedly found alongside 'mystery bones' at Sydney construction site

A backpack belonging to a Sydney teenager murdered more than a decade ago has reportedly been discovered near mystery bones at a building site.

Lyndsay van Blanken, 18, was killed by her ex-partner William Matheson.

Her remains, stuffed into a cricket bag, were found about six weeks after she disappeared in November 2003, however her backpack was never found.

A NSW Police spokesman confirmed bones had been found at a construction site in Randwick about 1.45pm on Tuesday.

The bones have been taken to the Glebe morgue for forensic examination.

It is not yet known whether they are human remains.

The backpack of Ms Van Blanken was discovered near the bones, The Daily Telegraph reported.

Her discman was found in the backpack, the newspaper reported.

Matheson is serving a 25-year sentence after being found guilty of the murder.