The latest confrontation between Tonga and Fiji adds to the significance of an odd incident on an unpopulated reef 1500 kilometres north of New Zealand.

The Minerva Reefs have been part of Tonga for 40 years, but last year Fiji claimed them and sent its navy there to destroy navigation lights on the entrance to the lagoon.

Meanwhile, last week a Tonga navy vessel sailed into Fiji waters to take Fiji Lieutenant Colonel Ratu Tevita Uluilakeba Mara to Nuku'alofa. Mara was facing charges of plotting to overthrow dictator Voreqe Bainimarama.

Mara is from the Lau Islands, part of Fiji, but culturally and historically part of Tonga. In the 1850s one of his Tongan forefathers, Ma'afu'otu'itonga, a Methodist, waged war on the Fijian Seru Cakobau who was based on the island of Bau, just off shore from Fiji's main island of Viti Levu.

Cakobau ultimately won and Lau became part of Fiji. Bainimarama comes from the Bau line.

However, the Lau Islands provided the leader crucial to modern Fiji: Ratu Sir Kamisese Mara was Fiji's founding prime minister and later president. The runaway colonel is his youngest son.

The first broadside in the latest skirmish might well have occurred in 2009, when several yachts bound for New Zealand were chased out of Minerva Reefs' lagoon, a stopping point for those travelling here, by Fijian navy boats.

Minerva Reefs were claimed by Tonga in 1972 after the shadowy US Phoenix Foundation shipped in dirt and declared it a republic.

The late King Taufa'ahau Tupou IV loaded a ferry with soldiers, a convict work detail and a four-piece brass band and sailed the 500 kilometres to personally haul down the "Republic of Minerva" flag.

As he raised his own banner, he declared it a Tongan island.

The reefs have taken on more significance as their possession gives rights to lucrative undersea minerals. South Korean, Chinese and Australian interests are seeking prospecting rights in the area.

Fiji's Foreign Affairs deputy permanent secretary Sila Balawa said last year it objected to Tonga building structures on Fiji territory.

In November 2009 the Fiji patrol boats arrived in the lagoon and chased yachts away.

Coincidentally, an RNZAF Orion was flying over the lagoon as the events were taking place.

Canadians Paul and Mary Major, of the yacht Bella Via, blogged on their arrival of the Orion over the reef: "It was very comforting to know that the plane was out there looking out for us."

Peter Sidler, on the Swiss-registered yacht Green Coral heading for the Bay of Islands, told of the Fijians challenging three yachts: "We were given 30 minutes to prepare for departure and leave. We left the Minerva Reefs angry and frustrated and continued our journey towards Opua."

Tonga's Ministry of Lands CEO Dr Sione Nailasikau Halatuituia said at the time that a dispute was taking place but they were surprised by Fiji's actions.

"The king claimed in it 1972. Since then we have been maintaining patrol and put up a lighthouse for the safety of seafarers," he said.

"We have developed a lot, and we are surprised at what is happening."

The Pacific Forum recognised Tonga's annexation of Minerva in 1972 but Fiji, which is now suspended from the 16-nation body, has not formally accepted it.

Read more:

Fiji, Tonga war over Minerva Reef | Stuff.co.nz