This ceremonial axe most probably is from the Wahgi People of the New Guinea central highlands and dates to the early 20th century. It comprises a polished wooden shaft or handle, a greenstone axe head and a wooden counterbalance with these elements held in place by tightly wound cloth.
Such an axe was not intended for actual use but was a ‘prestige’ item – a store of wealth and an item to be seen with as a symbol of power and means.
A related example is illustrated in Wilson (2014, p. 88).
The example here has ample signs of age. The handle particularly has been worn smooth by handling and has developed a lustrous, honeyed patina. The greenstone axe head is without any significant chips. It has a natural inclusion that runs across it.
References
Wilson, N. (ed.), Plumes and Pearlshells: Art of the New Guinea Highlands, Art Gallery of New South Wales, 2014.