TOKYO, Dec 3 (Reuters) - Japan's Nikkei share average slid on Friday, dragged down by declines in SoftBank Group and other heavyweights, as investors assessed the impact of the new Omicron coronavirus variant.

The Nikkei share average lost 0.22% to 27,693.34 by the midday break, after rising as much as 0.3%. The index is set for a 3.6% weekly drop.

The broader Topix gained 0.55% to 1,937.06 and is on course to lose 2.4% for the week.

"Some investors are bullish on the market outlook after sharp declines, while others still remained sceptical and tried to figure out whether the Omicron variant could be contained by vaccines or spread further," said Shigetoshi Kamada, general manager at the research department at Tachibana Securities.

"Nikkei's heavyweights were being sold, particularly SoftBank Group. That explains why the Topix is up and the Nikkei is down."

SoftBank Group, which has a stake in Grab, slid 2.75% after the ride-hailing and delivery firm tumbled more than 20% in its Nasdaq debut on Thursday.

Chinese ride-hailing giant Didi Global, in which SoftBank Group invests, will delist from the New York stock exchange and pursue a listing in Hong Kong.

Fast Retailing, owner of the Uniqlo brand of clothing stores, fell 1.28% after the company's domestic same store sales fell for a fourth straight month in November.

Chip making equipment maker Tokyo Electron lost 2.8%.

Shares that were battered by concerns over the resurgence of the new coronavirus variant gained, with airlines and railways rising 3.53% and 2.15%, respectively.

Travel agency H.I.S gained 5.44% and KNT-CT Holdings jumped 7.31%. (Editing by Rashmi Aich)