Japanese shares tumbled on Monday with the Nikkei average sliding to its lowest level in 1-1/2 months, hit by worries about the damage that the Omicron coronavirus variant could inflict on the economy.

The Nikkei lost 1.63% to 28,283.92, a low last seen on Oct. 13, after sliding 2.5% on Friday.

The broader Topix .TOPX dropped 1.84% to 1,948.48, falling below its 200-day moving average for the first time since August 2020.

Sentiment deteriorated after Japanese Prime Minister Fumio Kishida said Japan will bar entry to foreign visitors from Nov. 30 as it seeks to respond to the new Omicron variant.

Travel-related sectors were the worst hit, with Tokyo Disney Resort operator Oriental Land Corp 4661.T falling 4.8%.

Central Japan Railway 9022.T dropped 4%, while East Japan Railway 9020.T lost 3.9% and Keisei Electric Railway 9009.T sank 7.6%.

Carmakers dropped as the yen bounced back against the dollar, with the Topix transport equipment index .ITEQP.T shedding 3.05%, its biggest fall in more than three months.

Nissan Motor 7201.T lost 5.6%, while Suzuki Motor 7269.T slid 3.9% and Honda Motor 7267.T slipped 3.8%. Industry leader Toyota Motor 7203.T fell 3%.

Still, some investors are cautiously buying on dip, drawing comfort from a report that a South African doctor who had treated cases said symptoms of Omicron were so far mild.

"When the Delta variant was designated as VOC (variant of concern) in May, the market went through a correction of about 7%. Considering the difference in the availability of vaccines and oral drugs for COVID-19 since then, I would think the market has more or less priced in the risk from Omicron," said Okasan Securities chief strategist Fumio Matsumoto.

Only one in every 14 stocks has gained. Turnover at the Tokyo Stock Exchange's main board soared to 3.394 trillion yen ($30 billion), about 20% higher than the long-term average.

($1 = 113.09 yen)

(Reporting by Hideyuki Sano; Editing by Rashmi Aich and Devika Syamnath)