Australian shares are set to open marginally lower on Monday, with sentiment likely cautious after the nation's most-populous state extended COVID-19 restrictions by a week while it hunts for the source of a small outbreak.

The local share price index futures fell 0.1%, a 25.8-point discount to the underlying S&P/ASX 200 index close.

The benchmark edged higher on Friday.

New Zealand's benchmark S&P/NZX 50 index fell 0.7% to 12,638.24 in early trade.