Hundreds of Myanmar villagers rallied Saturday against a controversial Chinese-backed copper mine, activists told AFP, reigniting a contentious issue that could pose an early challenge to Aung San Suu Kyi's new government.

The Letpadaung mine in the central town of Monywa has for years been dogged by complaints of land-grabbing, environmental damage and brutal police crackdowns on protesters.

Growing numbers of villagers have gathered over the past four days in the first major anti-mine demonstration since Suu Kyi's civilian administration took power this year, ending decades of military domination.

"Today we demanded our rights by showing up with over 200 local protesters," Khin Lae, a protest leader, told AFP.

"No one was hurt today. Yesterday there were some clashes between protesters and the police," she added.

Winbao -- the Chinese firm that jointly runs the mine with a major Myanmar military conglomerate -- said this year it aimed to start production in May after years of construction.

Winbao was not immediately available for comment.

Another protest organiser, Amar Cho, told AFP the demonstrations have swelled since Wednesday, as have the number of police dispatched to control the crowds.

Police sparked public outrage in 2012 when they moved to clear a protest camp near the mine using phosphorous cannisters, leaving dozens with severe burn wounds, including several monks.

Suu Kyi led a parliamentary probe into that incident, which attracted the ire of activists after it recommended construction be allowed to proceed.

Protests have continued over the years and crackdowns have also spurred bouts of anti-China demonstrations in Yangon and other major cities.

Renewed controversy could strain relations with China, Myanmar's largest trading partner and a key player in its foreign policy.

Suu Kyi, who now holds several top government positions, met with her Chinese counterpart in her first diplomatic foray as foreign minister last month.

China is by far Myanmar's largest foreign investor, with a cumulative total of $15.4 billion of approved investments, and the two countries also share a long and restive border.