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The largest military operation in the Pacific since World War II winds up in the Solomon Islands on Wednesday after a decade working to end deep-seated ethnic violence in the poverty-stricken nation.

The Regional Assistance Mission to the Solomon Islands (RAMSI) deployed in a fanfare of publicity in 2003 after a desperate appeal from Honiara for international assistance.

Since then, it has adopted a low-key approach to bringing stability to the nation of about 600,000 people, which lies 2,000 kilometres (1,200 miles) northeast of Australia.

At a ceremony in the capital on Wednesday RAMSI will mark the 10th anniversary of the mission and the end of its military phase, with future operations concentrating on policing and governance.

"I think it has to be rated a success, certainly in terms of restoring law and order," Jenny Hayward-Jones, a Melanesia expert at Sydney-based foreign affairs think tank The Lowy Institute told AFP.

"However, there's still not the level of trust from the Solomons population in their police that would have been achieved in 10 years."

When RAMSI was formed, the Solomons government was at the mercy of warlords, ethnic militants and a corrupt police force, with virtually no control outside the capital Honiara.

More than 200 people had been killed and tens of thousands left homeless as gangs from rival islands terrorised local populations, with Australia's then-prime minister John Howard warning the situation posed a risk to regional stability.

"A failed state in our region, on our doorstep, will jeopardise our own security. The best thing we can do is to take remedial action and take it now," Howard said at the time as the situation looked set to spiral out of control.

The answer was RAMSI, a peacekeeping force led by Australia with support from New Zealand and 13 other nations from the Pacific Islands Forum.

Its troops landed near Honiara on July 24, 2003, at Red Beach, symbolically selecting the site where US Marines stormed ashore in 1942 to launch the bloody Guadalcanal campaign against the Japanese.

Unsure of the reception the militias planned, they had shoot-to-kill clearance if engaged in a firefight.

However, resistance never materialised and within a few months most warlords had been arrested and their followers disarmed.

There have been isolated outbreaks of unrest since, including riots after elections in 2006, but New Zealand's Ministry of Foreign Affairs and Trade (MFAT) said the situation had stabilised.

Hayward-Jones said RAMSI had acted as a "quasi government" in the Solomons since then and was keen to have the administration in Honiara take responsibility for the country again.

"This 10th anniversary ceremony is sending a message that the Solomons is ready to stand on it's own two feet again," she said.