A major financial consumer group in Seoul lashed out at Visa Inc. on Monday for its plan to raise the fees for overseas credit card purchases by South Koreans, warning that it may launch a nationwide campaign to boycott the global payment network.

Visa announced that it would press ahead with the fee hike plan despite strong opposition from local card firms.

The California-based company argued that it's inevitable to jack up the fee rate from 1.0 percent to 1.1 percent starting next year due to increased facility investments in the nation.

The Korea Finance Consumer Federation described it as a "tyranny-style" behavior targeting South Korean credit card issuers alone, not their Chinese or Japanese peers.

"If the international fees are raised, domestic card firms, suffering a drop in profitability, will pass their burden to consumers in any form," it pointed out.

Visa is seeking a "unilateral step" to take advantage of its dominant market status in Korea, and lacks reasonable ground to make such a move.

The group said Visa has made massive profits in Korea by taking a "free ride" on the government's policy of promoting credit card use.

"It's trying to unilaterally raise the fees for South Korea only, although it should rather lower those as credit card use abroad (by South Koreans) has grown," it stressed.

Unless Visa withdraws the plan, the federation added, consumers will be united in staging a campaign to boycott its service.

Earlier this month, eight local credit card companies said they will consider legal action against Visa. (Yonhap)