An Indigenous heritage group is applying for an urgent order under federal laws for a halt to work on a proposed tram stabling yard at Randwick, following the discovery of thousands of artefacts at the site.

The discovery of some 22,000 artefacts, many of which are said to come from outside Sydney, has potentially shone a light on Indigenous trade and transit routes through the region.

But the discovery could also lead to delays of the construction of the $2.1-billion light rail line from the city to the eastern suburbs, planned to be open within three years.

On Friday, Transport for NSW said the area contained a "substantial collection of tools and stone off-cuts, suggesting this was the site where such things were manufactured".