Dec 30 (Reuters) - Australian shares are set to gain at the open on Thursday, as investors look to shrug off concerns surrounding outbreaks of the highly infectious Omicron coronavirus variant and finish the year on a positive note. The local share price index futures rose 0.1%, an 89.8-point discount to the underlying S&P/ASX 200 index (.AXJO) close. The benchmark ended up 1.2% to close at its highest level since Sept. 8 on Wednesday. New Zealand"s benchmark S&P/NZX 50 index (.NZ50) rose 0.3% in early trading.