South Korea's two top technology firms, Samsung Electronics and LG Electronics, have a history of bitter rivalry, but their latest spat over a handful of washing machines has prompted a barrage of public mockery.

"This is all so petty and juvenile," a reader on online portal Naver said of the dispute, which began in September when Samsung accused LG executives of damaging its washing machines at stores in Germany ahead of an industry event.

LG agreed to pay for what it called accidental damage to four machines following mediation by German authorities, but couldn't resist taking a pot shot at its rival's build quality.

Samsung railed against those "slanderous claims" and filed a formal complaint at home, triggering a raid of LG offices by Seoul prosecutors on Friday and a travel ban on LG's head of household appliances.

"This is a mudslinging match," said Park Ju-gun, head of corporate watchdog CEO Score.

"Both Samsung and LG will have a hard time getting the public to understand why things have gone on this way, and there is not a single thing for either party to gain from this," he said.

That bemusement, punctuated by a collective snicker, found a voice online.

"If all that has been said is true, then this is nothing but a petty dispute you'd expect from street corner shops and not global companies," said a reader on the Nate portal.

On the streets, too, the comments were scathing.

"This incident shows the problem with the corporate culture in South Korean conglomerates," said Lee Hyeon-woo, an office worker in Seoul. "The mentality of these companies is not 'We're number one' but 'We must take down rival X'."

The cross-town rivals compete on several fronts, especially televisions and home appliances, and have a history of feuding.

They have quarrelled publicly over whose refrigerator could hold more, and who had a bigger share of the domestic air conditioning market, and current and former workers say they routinely spy on each other at trade shows.

Samsung declined further comment. LG said it has been cooperating with prosecutors, who would not disclose details of the investigation.

Neither company appears ready to let the matter drop. LG has filed its own complaint with prosecutors accusing Samsung employees of deliberately concealing and tampering with evidence. - Reuters