SEOUL - South Korea is discussing with the US various ways to set up a bilateral foreign exchange swap line as part of a trade deal over concerns about how proposed US investments could skew the local currency market, the country's finance minister said.

Minister Koo Yun-cheol made the comment at a parliamentary session on Monday as he answered a lawmaker's question about the need to request a conditional swap line, if not an unlimited one.

Koo put the maximum amount of direct investment South Korea would be able to make in the US each year at around $20 billion, without depleting central bank reserves, compared with $350 billion agreed in the initial deal reached in July.

South Korea's stance has been that the $350 billion would mostly comprise loans and guarantees, with limited direct investment, given the foreign exchange implications, while US President Donald Trump had said South Korea would pay "upfront".

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Koo said at the hearing he believed Washington now understood South Korea's concerns "to some degree".

Foreign Minister Cho Hyun, in a different session held on Monday, said there had been "some positive signals" from the US.

South Korea's presidential office also said in a separate notice there was some response from the US on a revised proposal made by Seoul last month, without elaborating. The proposal included a request for a currency swap line, Presidential Secretary Kim Yong-beom said earlier this month.