While metallic goods may have circulated between societies closest to Southeast Asia, they were likely quite rare and never achieved broader circulation across Oceania.

Though there was trans-Oceanic trade taking place, it was by and large regionalized in nature. For instance, while the archipelagos of Samoa, Tonga, and Fiji have an entangled history of political and economic exchanges taking place, their contact with more distant archipelagos was far more limited. Typically Oceania networks of exchange appear strongest when islands are first settled and people maintain closer relationships with origin islands, but those tend to fade over the generations and there needs to be some impetus to maintain long distance networks. In the case of Samoa, Tonga, and Fiji, they were fairly close together (from an Oceanic point of view) and there were important material exchanges taking place; whether prestige goods like fine woven mats, tapa cloth, red feathers-- or material goods such as lumber, adzes, or weapons. Additionally, long term historical entanglements through royal genealogies, conflicts, and land claims, meant there was a reason to maintain the regional network.

Further afield, there was less reason to maintain a connection with the people who sailed over the horizon to the Marquesas or Society Islands. There is evidence that some voyaging took place and the map Tupaia drew for Captain Cook reveals knowledge of Samoa and island chains further to the west, though Tupaia explains that he has never been there. Tupaia translated the traditional knowledge of the navigators which was encoded in song, chant, and story into a European style map, though one that placed islands based on their voyaging time rather than physical distance. What this can tell us is that while knowledge existed among some voyaging traditions of more distant islands, generally speaking navigators like Tupaia only moved across their local Oceania neighborhood (which is still an incredibly expanse of ocean).

As trade networks were typically more regional for Oceanic peoples, there would not have been constant opportunities for metallic goods to move far across the Pacific-- especially if those metallic goods held some prestige value for people in more localized or regionalized trade networks. This is perhaps especially true if the metallic good exists in some form beyond cultural reckoning. For instance, a metal knife can readily be understood as a cutting instrument of some utility, but a small coin has less apparent value than being a curiosity. If you are trading for goods, you're likely to focus on things that have prestige or utility within your cultural context. Nicholas Thomas' Entangle Objects 1991 remains a classic on the topic of exchange in the Pacific and one responding to some extent to Marcel Mauss' The Gift: Forms and Functions of Exchange in Archaic Societies 1966.

It is of course difficult to prove a negative, but it is also likely that any metallic goods which were traded might simply have rusted away or been lost and the amount of trade taking place between islands in Near Oceania and Southeast Asia was not likely very great. New Guinea is the obvious site for any sort of exchanges to take place as the rest of Melanesia sits beyond trade routes used in Southeast Asia and there is definitely evidence of contact and exchange taking place on the West side of the island-- but even those exchanges, between Hindu or Islamic Kingdoms and Western Papua-- only pre-date the arrival of Europeans into that theatre by a couple hundred years at most. New Guinea is a formidable island to cross by land or even sail around, it is incredibly diverse: ecologically, culturally, and linguistically due to its divided nature. All of this would have hampered the ability of metallic trade goods to move across the island and eventually be picked up by Melanesian populations to the East.

Finally, while metal goods were definitely in high demand when Europeans arrived, a major limiting factor on the value of metal goods was whether replacements could be had. If items rusted or dulled, then they needed to be sharped, repaired, or replaced. If this was impossible, then there was often less incentive to give up local tools and practices and therefore less value placed on metal goods. Dorothy Shineberg has a classic examination of local economies and how they influenced the sorts of goods Europeans carried in her book They Came for the Sandalwood. There had to be a market and demand for metal goods for them to be valuable. The technology itself was not inherently useful since few islands in the Pacific-- nearly all of them in Near Oceania (closest to Australia/Southeast Asia) have any significant mineral reserves to make new goods. Most of those that due have mineral deposits do not have ones that are easy to access without modern processing or mining techniques.

So why didn't metal goods flow across the Pacific? They were likely limited in nature, traded in limited places, perhaps not in a useful form, may have easily worn out/rusted, and trade networks tended to be local or regional. While its possible some goods could have gone far, there is no evidence of it, a number of limited factors, and so even if it happen it did not make a huge impact.