The reports in a number of publications have been accompanied by speculation that the defections signal a growing instability in the North Korean leadership under Kim Jong-Un.
In a lengthy commentary, the North's official KCNA news agency dismissed the reports as wild rumour and "sheer lies".
"The false propaganda ... Is a foolish and base politically-motivated conspiratorial farce" aimed at giving the impression of a mood of "uneasiness and horror" within the ranks of the North's top officials, it said.
Channel A - a subsidiary of the conservative Dong-A Ilbo daily - reported last week that Lieutenant General Pak Sung-Won, a deputy chief of the General Staff of the North Korean army, had escaped to Seoul via Moscow.
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KCNA said the report was "sheer nonsense" and stated that Pak was currently commanding a construction project at the Masikryong Ski Resort - a pet project of the supreme leader.
The commentary also took issue with the recent report of an execution - apparently that of two North Korean students for watching pornography.
South Korea broadcaster YTN recently reported the defection of three officials from Office 39 - a secretive government division devoted to acquiring hard-currency funds for the regime.
Yonhap news agency also published a series of articles regarding the recent defection of around 10 middle- to high-ranking officials.
None of the reports have been officially confirmed by South Korean authorities.
But the South's National Intelligence Service (NIS) reported in May that the North's defence minister, Hyon Yong-Chol, had been purged and most likely executed for insubordination and dozing off during a formal military rally.
Speaking at a forum in Seoul today, South Korean Foreign Minister Yun Byung-Se said Kim was overseeing a "reign of terror" that had prompted a number of North Koreans working overseas to defect.