Dec 21 (Reuters) - Australian shares are set to open slightly higher on Tuesday, even as uncertainties surrounding the Omicron coronavirus variant continue to keep markets on edge, while a slump in oil prices is expected to hurt domestic energy stocks. The local share price index futures inched 0.1% higher, a 91.2-point discount to the underlying S&P/ASX 200 index (.AXJO) close. The benchmark closed 0.2% lower on Monday. New Zealand"s benchmark S&P/NZX 50 index (.NZ50) fell 0.3% in early trading. Reporting by Harish Sridharan in Bengaluru Editing by Chris Reese