A climate change protest on Sunday disrupted operations at Newcastle, Australia's largest coal export port, on the country's east, leading to the arrest of 21 people. It was the second protest in two days to disrupt shipping at Newcastle.

The group of climate activists, Rising Tide, was responsible for the action, said that more than 30 climate activists had, that morning, paddled kayaks into the shipping lanes of Newcastle, breaking an exclusion rule.

The port, located 170 kilometers north of the Australian state capital of Sydney on the east coast, is the country's largest bulk cargo port, a nation that is divided over the issue of climate change.

"All cargo shipping has now been canceled due to the protestors' interference," a spokesperson for Newcastle Port, adding that the shipping of alumina, which is bound for Australia's largest aluminum smelter, Tomago, "has now been disrupted." The spokesperson said that coal ship had earlier been refused entry to the port due to safety concerns over protesters in the water.

Police said in a statement that 21 people were arrested and during the protest on Sunday "over alleged marine-related crimes."

Greenpeace Australia Pacific said that three of its activists scaled a coal ship near the port and stopped it operating as part of a "peaceful protest."

On Saturday, a protest in Newcastle forced a ship entering the port to turn around, with police arresting 1 people. Last year, similar days-long climate actions led to the arrests of 170 protesters.

Coal is one of Australia's largest commodity exports, only to iron ore.

The latest update is that Newcastle Port will resume operations on December 1.