(Adds reaction by Greek environment ministry)
ATHENS, April 16 (Reuters) - Thousands of workers at a Canadian-run gold mine in northern Greece protested in Athens on Thursday against a decision by the new leftist government to revoke the company's licence to develop the mine.
The government said that no job would be lost and accused Vancouver-based Eldorado Gold of using the workers to get away with illegal and anti-environmental practices.
Eldorado has spent about $400 million in the gold mine project in Skouries, in the lush forest of Halkidiki, since 2012. It wants to invest another $700 million by 2017 to build a processing plant and develop two mines in the area.
The investment has been a test case for Greece's will to attract foreign investment after years of austerity-induced recession.
"Eldorado Gold ... should realise that it cannot blackmail the country and the government," the environment ministry said in a statement.
"The government will defend until the end environmental protection and the public interest."
The development has stirred violent clashes between the mine workers and opposing local communities who say it would destroy the environment.
In a rare rally of this scale in favour of the project, thousands of workers worried about their jobs gathered outside the environment ministry and marched to parliament. They wore safety vests and helmets and waved flags which read: "Yes to mines, yes to growth."
About 2,000 people are currently employed by the project and the company planned to hire another 1,000 by 2020.
"We will not negotiate our right for employment, for dignity," representatives of the workers said in a statement.
A protest against the project has also been called for the evening.
Prime Minister Alexis Tsipras's government, which took power in January on promises to end austerity and reverse privatisations, revoked Eldorado's licence in February, saying it wanted to examine whether it was in line with town planning and environment regulations.
Eldorado said the government's decision could force it to reconsider its investment plans.
(Reporting by Angeliki Koutantou and Alkis Konstantinidis; Editing by Karolina Tagaris and Robin Pomeroy)