The Australian Federal Police has donated dozens of semi-automatic rifles to the Royal Solomon Islands Police Force (RSIPF), in what diplomats have called a "landmark" step up in security cooperation.

However, the announcement has been slammed by opposition leader Matthew Wale, who has warned against the "militarisation" of Solomon Islands and accused Australia of making the donation purely to stop China building up its influence in the police force.

The 60 MK18 rifles — along with 13 new police vehicles — were handed over to Solomon Islands police at a ceremony in the capital, Honiara, on Wednesday morning.

In a statement, the Acting Commander of the AFP's Police Partnerships Program, Clinton Smith, said the weapons would provide the RSIPF with "enhanced capabilities to counter criminal threats and maintain peace and stability" ahead of the Pacific Games next year and the island nation's national elections in 2024.

"The AFP and RSIPF have a deep friendship that is regularly demonstrated through the sharing of resources and capability, to ensure current and future security challenges and needs in the region are met," he said.

"The AFP is proud to be the Solomon Islands' security partner of choice and will continue to work closely with RSIPF officers to ensure [their police] are trained and equipped to provide the Solomon Islands community with an efficient, modern police force."

However, Mr Wale slammed the move late on Tuesday, saying he was worried that the guns would be used against protesters in the future.

"Obviously, we do not have external threats, so why the introduction of these high-powered guns?" he said.

Mr Wale said he was worried that Australia was being driven by its "anxiety" about China's growing cooperation with Solomon Islands police.

"It is clear Australia is anxious that, if they do not supply guns, then China will," he said.

"Geopolitical interests has surpassed national interests in this country and it is a sad state of affairs," he said.

Australia has long been the dominant international partner for the Royal Solomon Islands Police Force, but China has recently been rapidly expanding its own police training programs in the country.

Over the past year, Chinese police have provided riot gear and dozens of replica weapons to Solomon Islands police for training, run training programs in multiple provinces and recently sent a cohort of 32 local officers to China for a training course.

Police rearmament also remains a deeply sensitive topic in Solomon Islands, which was roiled with ethnic violence for years before Australia led a regional assistance mission to restore order in 2003.

Before then, militias raided police armouries and used the weapons to fight battles and extort locals.

When Australian troops arrived in the country, they destroyed thousands of weapons handed in during a gun amnesty. The AFP only began to gradually rearm Solomon Islands police from 2013.

A contingent of Solomon Islands police officers were trained with the MK18s in Brisbane earlier this year, and conducted live-fire drills in July.

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On social media, Australia's High Commissioner to Solomon Islands, Lachlan Strahan, stressed that the firearms came with "stringent training and rigorous safeguards, including concerning safe and secure storage".

The weapons will only by used by the RSIPF's elite Police Response Team, and will not be available to regular officers, who do not carry firearms.

The AFP has also stressed the agreement to provide these new firearms formally occurred during the development of the RSIPF AFP Policing Partnership Program, which commenced in July 2021.

That's several months before China started its own cooperation program with Solomon Islands police, in December of that year.