A climate protest flotilla at the Port of Newcastle forced the coal carrier Cemtex Leader to abort its arrival at the world's largest coal export hub on Saturday, reports Saint Petersburg's PortNews.

New South Wales police charged 11 people during what authorities described as a high-visibility operation after protesters entered a temporary exclusion zone covering most of Newcastle harbour. Those charged face alleged marine-related offences under the state's Marine Safety Act and anti-protest laws allowing fines up to A$1,100 (US$70) and prison terms of up to two years.

Rising Tide, organiser of the five-day "People's Blockade" at Muloobinba/Newcastle, claimed a total of 19 arrests. The group said kayakers, swimmers and a small boat entered the marked shipping channel to obstruct an incoming vessel. Ten swimmers, four kayakers and five people on a small boat ��including members of the Knitting Nannas and Hunter Valley grandmothers Lynn Benn and Julia Lee - were detained, with some later released without charge.

Rising Tide said police briefly lost control of the channel as the flotilla expanded across the exclusion zone.

The Port of Newcastle said only one vessel had been prevented from entering and that shipping movements have not ceased and will continue as scheduled.

The protest followed advance warnings from authorities. Two days earlier, NSW Police urged participants to follow safety instructions, while Transport for NSW had already imposed an exclusion zone.

The confrontation occurred after the official launch of the blockade at Horseshoe Beach, where organisers said more than 500 people took to the water following a rally featuring coal workers, students, Torres Strait Traditional Owners, Pacific church leaders and Australian Greens leader Larissa Waters.

Local officials estimated the event could attract around 5,000 people. Statements from arrested participants linked their actions to concerns about climate risks and community impacts when coal companies move on from communities after extracting resources.

Rising Tide is calling for a halt to new coal and gas approvals and for higher taxes on fossil-fuel export profits to support a "just transition."