South Korea has found excessive levels of the cancer-causing chemical dioxin in Chilean pork, according to the agriculture ministry in Seoul.

Some pork in a seven-tonne shipment from Chile, imported on 11 June, was found to contain 7.5 picograms of dioxin per gram of fat, exceeding South Korea's limit of 5.0 picrograms per gram of fat, reported Reuters. A picogram is a trillionth of a gram.

"As the quarantine office detected dioxin in Chilean pork, we will intensify dioxin tests on pork from Chile," the ministry was quoted as saying by Reuters.

"We will ask Chile to investigate a source of the contamination and to stop pork exports from the export line to ensure safety," it added.