In September Dalwood at Branxton, Australia's oldest continuous commercial vineyard, will celebrate 189 years since George Wyndham first planted grapes there in 1830.

An open invite has gone out to descendants of all the convicts, indigenous people, Bounty immigrants, German vine-dressers, children and anyone else who worked there to attend.

"Honestly, we don't know if we'll get 100 replies or 400," said Don Seton Wilkinson, event organiser and Secretary of the Dalwood Restoration Association.

"After all, there are links here going back the best part of 200 years. That's why we're having an August 15 date for replies, so we can work out the catering."

Mr Seton Wilkinson said Dalwood was massive in its heyday.

"Back in George Wyndham's day Dalwood was about 3,500 acres, which required a huge staff," he said.

"We believe there were 70 or 80 families working at Dalwood. It was an incredibly diverse workforce."

Wyndham also established the first Hereford cattle herd in NSW, built the first Greek style building in Australia (Dalwood House), and had one of the largest and most successful horse studs in the colony.

George and Margaret Wyndham arrived in NSW from England on Boxing Day 1827 and purchased Dalwood in January 1828.

They subsequently acquired other properties - Mahngarinda (Merriwa), Colly Blu (Liverpool Plains), Bukkulla and Nullamanna (McIntyre River), and Keelgyrah (Richmond River).

Any descendants, including those who worked for his son John Wyndham, are welcome to attend.

The names of 180 convicts have been identified so far. Those interested in attending should email secretary@dalwood.org.au