North Korea has slammed efforts to surveil its illicit trades with its exports to China reportedly on the rise.

Earlier this month, France and Canada dispatched military aircraft to a US Air Force base in Japan with the intention of monitoring Pyongyang's "illicit maritime activities" including ship-to-ship transfers involving North Korea-flagged ships evading United Nations sanctions.

On Tuesday, a North Korean foreign ministry researcher called the move an "imprudent" act, according to Seoul's Yonhap News Agency.

"[The aircraft will] destroy security balance in the region and result in aggravating the political situation," the researcher reportedly said.

The Financial Times reported on 20 October that Chinese customs data showed that the trade between North Korea and China has risen to its highest levels since December 2019. North Korea has sent $14.3m worth of goods to China in September, up from $6.2m in August.

China, meanwhile, sent $55.6m to North Korea in September, surging from $22.5m in August.

The UN Security Council has maintained a series of sanctions on Pyongyang, restricting all sorts of trades, including oil exports and coal imports, with the US maintaining its own more expansive set of blacklistings.

Sanctions were levied often in response to North Korean missile tests, which the country continues to carry out, including last week's launch of a submarine-based missile.

Still, North Korea manages to make some exports, reportedly often using the Ningbo-Zhoushan area for ship-to-ship transfers to help conceal the origin of the cargoes.

According to the Ministry of Foreign Affairs of Japan, many countries, including the UK, Australia and New Zealand, have sent forces to the country to keep tabs on North Korean shipping.