How big are they? How thick?
Ceremonial and bridal axes are huge and thin. Old ceremonial axes were usually functional weapons (usually used for killing downed and wounded enemies, before they got steel axes), but too fragile to be tools. Bridal axes aren't usually very sharp. These don't look like bridal axes to me - either too thick or too small.
If smaller (perhaps 10-15cm long), and thicker (perhaps more than 2cm thick), it's a work axe, as used for felling trees before they got steel axes. They're not used in the same way as a steel axe, but lots of short chops. Steel-axe-style big swings are too likely to break them. If you've cut down a tree with a stone axe, you appreciate the value of steel axes. I don't know if work axes like these were used as weapons, but they'd manage OK, as very close range weapons.
If that size or smaller, with an asymmetrically ground edge, then it's an adze head or chisel blade.
Since they're pretty labour intensive to make, and suitable stone isn't available elsewhere, polished axe heads would be traded long distances in Australia, Melanesia, and Polynesia. But their primary function was as tools as weapons. After steel axes, then there isn't so much demand, and then you see things like specialised bride-price axes. So lots of the recent ones are the thin-bladed huge bridal axes, and those are the ones that get collected by tourists (common because they're modern, decorated hafts, and spectacular). I think work axes just get called "bride price" axes by association with their larger bridal brethren.
Perhaps of interest:
http://australianmuseum.net.au/movie...-axes-of-mendi
http://australianmuseum.net.au/movie/tree-feeling-axes