Workers inside the factory say they will stay for "as long as it takes"
The company at the centre of a sit-in protest on the Isle of Wight has said it is moving because the wind turbine market in the UK is "not big enough".
Vestas Wind Systems told the BBC that even though demand was strong globally it made "more sense" to make turbines as close to the market as possible.
It comes on the fifth day of a sit-in protest by 25 workers inside the plant demonstrating against job cuts.
Hundreds have attended a rally for the protesters in Newport, a worker said.
Vestas worker Sean McDonagh, 33, said he believed at least 400 people gathered at St Thomas' Square on Friday evening.
"It was overwhelming," he added. "The faces in the crowd tonight were islanders and there was a sense of unity."
Mr McDonagh said the demonstrations would now be daily.
Peter Kruse, spokesman from Vestas Wind Systems, told the BBC they were "patient people" but the workers - who are not members of a union - had been warned that there will be "consequences".
He said: "We have told them that it (the sit-in) can have consequences. We are talking to the people inside. They will not starve, we will cater for them with proper meals.
"We are patient people and have a lot of time, we strongly hope for a peaceful solution and a dignified solution.
"It's normal that people are angry and frustrated and unhappy with what's going on."
The company moved to the island in 2000 because of skills possessed in the fibreglass yachting industry.
Mr Kruse said things moved "very slowly" onshore in the UK and the company would now develop a plant in the US.
He said: "It makes more sense to make the turbines as close to the market as possible.
"There is a market in the UK but it's not big enough for the time being."
A protest began on Monday after plans were announced to cut 625 jobs despite rising profits. Workers barricaded themselves inside an office.
The factory, which makes wind turbines, is believed to be shutting next Friday.
One of the workers staging the occupation, Ian Terry, told the BBC they would not be moved, even by the threat of criminal prosecution.
He said: "The company's made no losses, only massive profits. The reason that they're moving abroad is to maximise profits more than to secure the future of their company.
"So I think we have a worthwhile fight and being threatened with criminal charges, it doesn't really wash with us."
Speaking from inside the factory a worker told the BBC everyone seemed to be in "good spirits".
He added: "There's a few sore backs from sleeping on the floor so we are a bit achy but apart from that it's going well, we are remaining strong.
"People are coming along to show their support and that means a lot to us, the more support we get the better.
"This is for the island and we have to save these jobs, there's lots of families affected."
He joked that security guards were trying to tempt them out with the smell of bacon being cooked from inside in the building.
Protesters survived on cheese rolls, oranges and cans of fizzy drinks yesterday, which had been supplied by the Danish-owned company.
A total of five men have now been arrested at the site, police said.