Customs administration spokesman Huang Songping said exports to the hermit nation rose 29.1 percent in the first six months of the year, although imports were down 13.2 per cent.
But Huang said imports from North Korea have sharply decreased every month since March and insisted that Beijing was upholding United Nations sanctions against Pyongyang over its nuclear programme.
"Simple accumulated data cannot be used as evidence to question China's severe attitude in carrying out UN Security Council resolutions," Huang told a press briefing.
"UN Security Council sanctions are not a total ban on shipments. Trade related to DPRK people's livelihood, especially those that reflect humanitarianism should not be influenced by the sanctions."
Regional tensions escalated after North Korea successfully tested an intercontinental ballistic missile last week.
US President Donald Trump later complained that trade had gone up between the countries after he had called on Beijing to use its diplomatic and economic clout over its neighbour to convince Pyongyang to drop its nuclear programme.
"Trade between China and North Korea grew almost 40% in the first quarter. So much for China working with us -- but we had to give it a try!" Trump tweeted on July 5.
