Originally it was MAF, the F of food being implied.
New elections, new government, everything was shuffled, food was added.
2006: New elections, new…, ah well you know, the F for fisheries was added, it became MAFFF.
2016: New government… fisheries became a ministry on its own (again), back to MAFF. But some places still refer to MAFFF
Any time you import of export goods to or form overseas, you will have to pass through customs. And customs is obliged to check that you have the proper quarantine papers, making sure that your animal or plant products do not contain pests.

The normal mateloi, sensitive plant, (mimosa pudica) is already a pest enough, now imagine one up to 2 m high and with even bigger and sharper spines. It has invaded all neighbouring islands, including Niuē, although it has been largely eradicated there now. Until April 2009 Tonga was the only country free of it, then suddenly it showed up in Fangatongo (Neiafu). But at that time your quarantine department was able to kill them all.
For more information (pests only) see Pacific Island Ecosystems at Risk.
Or look in the Tongan Wikipedia.
