North Korea launched a vicious personal attack on South Korean President Park Geun-Hye Sunday, calling her a "prostitute" in thrall to her "pimp" Barack Obama, as it said it was ready for "full-scale nuclear war".

In a diatribe that was strongly worded even by the standards of its normally florid prose, the North lashed out at the relationship between a "master and its puppet" and threatened Park would pay a "dear price".

"Park Geun-Hye's recent behaviour with Obama was like a mean, immature girl begging gangsters to beat up someone she does not like," said the Committee for the Peaceful Reunification of Korea (CPRK).

"Or a crafty prostitute eagerly trying to frame someone by giving her body to a powerful pimp," it added, according to the Korean Central News Agency (KCNA).

KCNA's official English translation of the Korean-language dispatch offered "capricious whore" as its description of Park.

The vitriol came the day after US President Obama wrapped up a two-day visit to the South, during which he called the North a "pariah state" whose isolation would deepen further if it pushed ahead with a feared fourth nuclear test.

Recent satellite imagery has revealed heightened activity at the North's nuclear test site, and Park warned Friday that Pyongyang was ready to stage another atomic test anytime.

Both presidents cautioned that defiance of international rules would mean harsher sanctions on the impoverished country, and urged China to discourage its wayward ally from a new provocation.

The CPRK, the body tasked with handling cross-border affairs, slammed the pair's remarks as "intolerable insults" against its leadership.

"If Obama and Park Geun-Hye believed that they could change our minds with such threats and blackmailing, they can't be more foolish," it intoned.

"In particular, Park Geun-Hye continued to viciously take issue with our dignity, system and nuclear programmes," it said, characterising her remarks as "froth(ing) at the mouth".

"She thus laid bare her despicable true colours as a wicked sycophant and traitor, a dirty comfort woman for the US and despicable prostitute selling off the nation," the KCNA translation said.

The allegation that Park is a "comfort woman" -- a euphemism for women enslaved to provide sex to Japanese soldiers in World War II -- will likely prove extremely controversial in South Korea, where it remains a hot topic in relations with Tokyo.

The CPRK also denounced Obama, whose visit was "utterly indifferent to the sorrow" felt in the South over the sinking of a ferry full of schoolchildren.

"Had Obama even an iota of ethics and morality, he should have postponed or shelved his trip," the KCNA translation said.

"The latest visit by Obama only reaffirmed our long-held belief that might, not words, are the only option to deal with the old enemy US and strengthened our resolve and determination to stick with our policy to fight a full-sale nuclear war.

"Park Geun-Hye will pay a dear price for abandoning the opportunity we earlier gave and choosing a path of anti-unification and anti-peace and a path to confrontation and war.

"(She) will feel to the marrow the merciless power of the anger felt by our troops and people."

The latest invective follows months of increasingly colourful personal attacks on Park.

Her predecessor Lee Myung-Bak was also the target of highly personal criticism by the North's state media, but the attacks on Park have been notable for their repeated allusions to her gender -- she is Seoul's first woman president.

Pyongyang earlier likened her to a "peasant woman babbling to herself in the corner of her room" and derided her as a "low-quality politician" who talks "nonsense gibberish."

Since assuming office in February 2013, Park has repeatedly spoken of her desire to build trust with Pyongyang while remaining firm in the face of any provocation.

The policy was not gone down well in Pyongyang, which has angrily rejected her proposal to prepare for unification as an attempt to absorb the North into the South.