Construction is underway on Australia's biggest glasshouse, in the New South Wales Hunter Valley, which is solar powered and already providing employment opportunities for new migrants and refugees.

Excavators have started the groundwork on the vegetable growing facility at Fullerton Cove, about 40 minutes outside of Newcastle.

At more than 16 hectares, it will cover the size of 20 rugby fields.

Dutch investor Cor Disselkoen has developed glasshouses throughout the Netherlands and has brought in materials and labour for construction here.

Once operating, the facility will produce 15,000 tonnes of tomatoes, cucumbers and capsicums every year.

"We are producing 14 times more per square metre so we have a huge production compared to open field growing," Mr Disselkoen said.

"It's year-round, reliable, independent from whatever climactic circumstances so we can guarantee year around delivery to our clients."

It has taken many years since the project was first announced to get to this point, after assessments in both Port Stephens Council and the Joint Regional Planning Panel.

The project was mired in controversy initially, over plans to power it with a nearby coal seam gas well.

But now it will be run solely on clean energy.

"We don't get any natural gas or coal to fire or heat, we don't use any electricity from coal fired electricity mains," Mr Disselkoen said.

"We catch the rainfall, which falls on our roof, which is enough for us to grow our plants."

"It's the most efficient way, but environmentally the best way to do in the future."

Glasshouse employs refugees and migrants

Refugees and migrants in the Hunter region will be among the 125 workers employed at the glasshouse.

One of them, Tilahun Mengistu who came with his family came to Newcastle from a Kenyan refugee camp six years ago, is already employed providing catering for the construction crews, and will also assist with transport.

Tilahun Mengistu is a Kenyan refugee who is employed to provide catering for the construction crews. ( ABC News )

He said while he was lucky to find work when he moved to Australia, other refugees struggled.

"It's really very hard," Mr Mengistu said.

"Coming to a new country, completely different from where you came from, you have to start from scratch."

He said the farm would be a major employment opportunity for dozens of people starting lives in Australia.

"You often see people moving out of Newcastle because that sort of opportunity is not there for them," Mr Mengistu said.

"Employment for refugees from non-English speaking backgrounds is difficult."

Government welcomes growth to agriculture industry

NSW Primary Industries Minister Niall Blair said the new facility would help ensure more local produce was grown and consumed.

"[It] means that we can grow different crops out of season and capitalise on some of the markets that traditionally we may have had to rely upon imported products for," Mr Blair said.

Construction is underway on the glasshouse in the Hunter Valley region of NSW. ( ABC News )

Mr Blair said the alternative farming method worked side by side with traditional practices and will help grow the $15 billion primary industries sector.

"When we look at glasshouse and intensive production it's something that we've done a lot of investment and research into through the Department of Primary Industries," Mr Blair said.

"It's something that we see the industry is doing in other parts of the state and it's something we're confident will be another component to the different ways we produce food and fibre in NSW.

"Food production is something we're all very concerned about [and] something I know there are more people passionate about in NSW, so looking at different ways that we do it, utilising different resources is something we encourage."