Trash-carrying balloons floated from North Korea are spotted from the South Korean border town of Paju on Thursday. (Yonhap)

North Korea floated trash-carrying balloons into South Korea for a second straight day on Thursday, South Korea's military said, the latest in its repeated provocations Seoul condemned as "senseless."

The Joint Chiefs of Staff (JCS) said it detected the North launching some 480 trash balloons from late Wednesday until 12 p.m. Thursday, with around 100 trash bundles landing in Seoul and northern parts of Gyeonggi Province that surrounds the capital.

In a notice sent to reporters at around 7 p.m., the JCS said the North appears to be once again sending balloons across the border, warning the public to be careful of falling objects and refrain from touching them.

Trash bundles that have been retrieved so far largely contained scrap paper and plastic bottles, the JCS said. No hazardous substances have been found.

The series of launches that began Wednesday marked the resumption of the North's trash balloon campaign after a near monthlong halt.

Since late May, the North has launched thousands of balloons carrying trash in a tit-for-tat move against anti-Pyongyang leaflets sent by North Korean defectors and activists in South Korea. Pyongyang last launched such balloons on Aug. 10.

In response to the North's campaign, South Korea's military began blasting anti-Pyongyang propaganda broadcasts daily through loudspeakers on the border in July.

North Korea has bristled against the anti-Pyongyang leaflet and loudspeaker campaigns on fears that an influx of outside information could pose a threat to the Kim Jong-un regime.

South Korea's unification ministry in charge of inter-Korean affairs condemned the repeated balloon campaign as "senseless."

"It is regrettable that North Korea has repeated the senseless and vulgar action at a time when damage from heavy rains is grave," a ministry official told reporters on condition of anonymity.

North Korea is struggling to recover from massive flood damage in its border areas along the Amnok River. Heavy rains in late July flooded large areas of the country's North Phyongan, Jagang and Ryanggang provinces.

The official also stressed that civilian activists' voluntary action to disperse information into the North can never be used as a pretext for North Korea's provocations against the South, referring to the anti-Pyongyang leafleting.

The launch on Thursday evening marked the 14th incident in which North Korea floated trash-carrying balloons across the border since late May.