Most Asian currencies softened on Monday, with the South Korean won leading regional declines, as mixed signals about the US-China tariff rollback dampened risk sentiment.

The won, the worst performing currency in the region this year, weakened as much as 0.4% against the dollar during the session.

South Korea's economy is highly sensitive to developments in the protracted trade war between the United States and China, given its reliance on tech exports.

US President Donald Trump said on Friday that he has not agreed to rolling backs the US tariffs sought by China, contradicting earlier reports of officials confirming the rollbacks.

Adding to the uncertainties, Trump over the weekend said talks with China were moving along "very nicely", but the United States would only make a deal if it was the right deal for America.

"We remain stuck to parsing the Sino-US trade headlines for short-term directional cues," OCBC said in a note, adding that "the bar for positive surprises on the Sino-US trade front may be getting higher and higher."

China's yuan was marginally weaker as factory gate prices in the country fell the most in more than three years in October, signalling continued weakness in the manufacturing sector amid falling demand.

While weak producer price inflation could reinforce the case for further policy stimulus by China's central bank, accelerating consumer inflation could reduce expectations of aggressive easing.

The Malaysian ringgit slipped 0.2% as government data showed industrial production in the country grew at a slower-than-expected pace.

Meanwhile, the Indonesian rupiah weakened marginally to 14,040 per dollar.

Bank Indonesia, earlier in the day, said all the central bank's policy instruments were set to support economic growth by maintaining price inflation and foreign exchange stability.

The central bank sees the currency trading at an average of 14,000 to 14,400 per dollar this year and around 13,900 to 14,300 in 2020.

The Philippine peso, the Singapore dollar and the Indian rupee faltered slightly.

The rupee on Friday eased 0.5% after Moody's cut its outlook on the country citing increasing risks that growth in Asia's third-largest economy will remain lower than in the past.