Several thousand Aboriginal artefacts recovered before construction of a NSW energy infrastructure project have been returned to Wiradjuri Country.

The more than 5,000 culturally significant artefacts were identified during heritage surveys and archaeological investigations undertaken prior to construction along EnergyConnect's 540km alignment between Buronga and Wagga Wagga.

The up to 3,000 year old artefacts — primarily stone tools and hearth-related material — were returned to Country by registered Aboriginal parties in repatriation and smoking ceremonies alongside Transgrid, its construction partner Elecnor Australia and subcontractor, Everick Heritage, following project completion earlier this year.

Transgrid said the discoveries provide valuable insights into Aboriginal occupation and cultural practices across the Riverina over thousands of years.

Wiradjuri man Mark Saddler, who was involved in the repatriation, said the cultural ceremonies and reburial ensure the artefacts remain protected and connected to Country.

"Renewable energy is a great thing for this area, because we do need it. But we must ensure that whatever construction projects are going to come through, we protect our places," Mr Saddler said.

"We have a responsibility to document and safeguard these artefacts, then return them to Country as close as where they came from, because our Elders left them there and that's where they should go back to.

"Archaeologists are highly specialised in their field, but Wiradjuri people are extremely trained and specialised in what we know, and it's important that we share that knowledge with people as much as we can."

Transgrid said cultural material recovered along the alignment was dominated by stone artefacts, with quartz accounting for more than 75 per cent of the collection.

Archaeologists also identified silcrete, basalt and other materials sourced from across the region, along with modified glass and porcelain that demonstrate the continuation and adaptation of traditional stone tool-making practices following European settlement.

Everick Heritage Archaeologist, Andrew Jenkins, said the archaeological investigations had helped build a detailed picture of Aboriginal activity throughout the Riverina, which highlights the remarkable depth and continuity of First Nations history.

"Using carbon dating and sediment dating, we've confirmed that some of these archaeological sites are up to 3,000 years old," Mr Jenkins said.

"The artefacts provide valuable insights into how Aboriginal people lived and travelled throughout the Riverina, including how they sourced materials, produced stone tools and used the landscape over thousands of years.

"The more data we have, the better we can understand what life would have been like out here."

Transgrid Executive General Manager of Corporate Affairs, Stakeholder Engagement and Environment, Maryanne Graham, said the repatriation ceremonies were the culmination of years of collaboration with Traditional Custodians across the EnergyConnect project.

"Returning these artefacts back to the land they came from is a meaningful way to conclude this stage of the project and honour our commitment to Traditional Custodians," Ms Graham said.

"Protecting cultural heritage and building respectful, long-term relationships with First Nations communities is a key part of how we deliver our projects.

"We're proud to have worked alongside Traditional Custodians to ensure these artefacts could be returned to Country in a way that respects cultural protocols and traditions."

With assistance from Everick Heritage, Transgrid is developing a digital showcase featuring some of the most significant artefacts recovered along the EnergyConnect alignment, documenting their journey from discovery through to repatriation and return to Country.

Elecnor Australia Environment Manager, Rebecca Walker-Edwards, said the team were proud to have been at the forefront of heritage work.

"Importantly, the repatriation process - along with all heritage work on the project - gave First Nations people the opportunity to spend time on Country they'd never seen. These are places where their ancestors lived," Ms Walker-Edwards said.

"EnergyConnect also provides this rare opportunity to study our First Nations culture and history across a large swathe or cross-section of New South Wales.

"It's rare that our scientific and cultural heritage can be studied at this scale.

"We hope the information gathered will provide lasting knowledge for our First Nations communities and their future generations."