Australia has deployed 23 Australian Federal Police officers, including tactical response teams to the Pacific island nation to help with stability.

An additional 50 AFP officers and 43 Australian Defence Force members will fly to the country on Friday.

Home Affairs Minister Karen Andrews said Australian forces had been armed with lethal and non-lethal weapons.

"Our role is to assist the Solomon Islands police force to restore law and public order as soon as we possibly can," Ms Andrews told ABC TV on Friday.

"This is a policing matter, not a military matter, so we are working very closely with the police force there."

Ms Andrews said Australia's deployment was in response to a request for help from the Solomon Islands government under a bilateral security treaty.

"We are not there to intervene in any way in domestic matters," Ms Andrews said.

Foreign Minister Marise Payne said it was likely the Australian deployment in the region would last for weeks.

While there was not an exact figure, she estimated there were 200 Australian citizens in the country.

"We will engage with them as we need to in terms of those who might wish to leave," Senator Payne told ABC Radio.

"Importantly, the travel advice is very, very clear about avoiding demonstrations and protests."

Solomon Islands Prime Minister Manasseh Sogavare imposed a lockdown in Honiara for 36 hours along with a curfew in a bid to quell the unrest.

The lockdown ended on Friday morning.

Mr Sogavare has blamed foreign powers for encouraging the unrest in the country.

But Solomon Islands opposition leader Matthew Wale accused the government of taking bribes from China, saying the people were protesting the current regime's corruption.

The widespread protests have largely started due to the island nation's decision in 2019 to switch diplomatic ties from Taiwan to China.

Media reports said people had travelled from the most populous province of Malaita to the capital because of concern about being overlooked by the national government.

The province opposed the decision to end diplomatic ties with Taiwan and establish formal links with China, resulting in an independence referendum last year which the national government has dismissed as illegitimate.

Prime Minister Scott Morrison said the Solomon Islands had first sought help from Australia and have not approached China to his knowledge.

He also sought to quell concerns from Solomon Island MPs that Australian intervention could prop up support for Mr Sogavare.

"They are not issues that Australia involves ourselves in," he said.

"We have Australians bravely going back to the Solomon islands to support our Pacific family, to ensure we have stability and peace, so they can resolve issues internally," he said.

Australian Associated Press