The Wall Street Journal on Wednesday reported that hundreds of thousands of South Korean-made shells were set to be delivered to Ukraine via the United States under a "confidential arrangement" between Seoul and Washington.

South Korea has a long-standing policy of not providing weapons to active conflict zones, which it has stuck to despite repeated requests from the United States, European allies and Ukraine itself for more help.

"The South Korean government's position on aid to Ukraine remains unchanged... and there are also inaccuracies in the (WSJ) report," Jeon Ha-kyu, the defence ministry's spokesperson, told reporters.

Jeon acknowledged that there had been discussions between the Pentagon and an unidentified South Korean company about "some ammunition exports", but declined to provide details.

"There have been many discussions and requests, so the Korean government will take appropriate measures while comprehensively reviewing the situation in Ukraine and the humanitarian situation," he said.

Cho Tae-yong, head of South Korea's national security office, told lawmakers Wednesday that "there is no support (in the form of) artillery shells to Ukraine."

South Korea, the world's ninth-largest arms exporter, has so far sent humanitarian assistance to Ukraine and sold tanks and howitzers to Poland -- a key ally for Kyiv as it battles invading Russian forces.

It has hinted that it could reconsider its policy of not supplying lethal aid, with the president's office saying last month that a large-scale Russian attack on civilians could tip the balance.

But experts warn that South Korea is in a tricky position because of its economic ties with Russia -- its 15th largest trading partner as of 2022 -- as well as Moscow's influence over nuclear-armed North Korea.

South Korea's "defence ministry is unable to specify what these 'inaccuracies' in the (WSJ) report are," Cheong Seong-chang of the Center for North Korea Studies at the Sejong Institute in Seoul told AFP.

It would be difficult for South Korea to disclose any such aid to Ukraine, he added.

"Cooperation with the United States is important for the Seoul government, but it also needs to maintain ties with Moscow."