By Sam Byford

TOKYO (Reuters) - Oil jumped on Monday as OPEC+ considers a cut to output this week, while Asia shares were mixed with holidays in the Asia-Pacific region likely to result in thin trading.

U.S. crude rose 3.01% to $81.88 a barrel after OPEC+ sources told Reuters oil production could be cut by between 500,000 and one million barrels a day. Brent crude rose 2.95% to $87.65 per barrel.

On the first trading day of the quarter, MSCI's broadest index of Asia-Pacific shares outside Japan was down 0.43%, on course to decline for a fourth straight session.

In Australia, where some states are observing a public holiday, the S&P/ASX 200 index fell 0.15%.

Hong Kong's Hang Seng index dropped 0.64%.

Japan's Nikkei 225 index, however, was up 0.72% after upbeat quarterly earnings from Mimasu Semiconductor boosted chip shares.

South Korea has a national holiday on Monday, while China has just entered Golden Week and Hong Kong has a holiday on Tuesday.

"Given the holidays, trading is likely to be thin," ING's regional head of research Robert Carnell said in a note.

The dollar traded flat against the yen at 144.75 after hitting a high of 144.89 overnight. Japan's finance minister Shunichi Suzuki said this morning the government would take "decisive steps" to prevent sharp currency moves.

Attention later in the day will be on September data for the U.S. ISM manufacturing index.

"ISM manufacturing is unlikely to dent the optimism around the US economy that has been building up further with positive economic indicators released over the last few weeks," Saxo Bank market strategist Redmond Wong wrote in a research note.

Tuesday will see the Reserve Bank of Australia meet, with markets widely expecting another 50 basis point rate hike, as well as the release of CPI inflation data from Japan.

Spot gold was up 0.47% to $1,667.2208 an ounce.

Leading cryptocurrency Bitcoin fell 1.15% to $19,200.