Solomon Islands' pro-China leader, Manasseh Sogavare, has withdrawn from the race to be the next prime minister following the country’s national election.

The controversial politician, who was in his fourth stint as prime minister coming into the April 17 election, announced on Monday (local time) he would not contest, saying he had been "vilified by media" and his family had been subjected to "unprecedented abuse".

His political party gained 15 seats at the national election, losing more than half of the 37 MPs it had going into the poll.

He will be replaced as his party's prime ministerial candidate by Foreign Minister Jeremiah Manele, who will aim to become leader on Thursday when new MPs sit in parliament to decide the prime minister.

It is still unclear whether Mr Manele will have the numbers to become prime minister.

Mr Sogavare made international headlines when he signed a controversial security pact with China in 2022 after switching the country's diplomatic relations from Taiwan.

Speaking at a press conference in the Solomon Islands capital Honiara on Monday night, Mr Sogavare thanked his "people and country" for the "privilege and honour" of serving as leader.   

But, he said, it was time to "usher in new party leadership".  

"I have been accused of many things [during my time as leader]," he said. "My family, and my children included, have been subjected to unprecedented verbal abuse. 

"I have been increasingly vilified in the media, our family home has been razed to the ground. 

"But that did not waver my resolve to serve my country. It is a monumental sacrifice."

Mr Sogavare's announcement marks the end of an era in Solomon Islands politics.

Known to Solomon Islanders as "Soga", he drove the country's controversial recent pivot towards China, which culminated in a secretive security pact.

The pact also influenced Australia's federal election and thrust the small island nation of 750,000 into the middle of a geopolitical tussle between the superpowers.

Despite violent riots in the capital in 2021 and attempts to oust him as leader, Mr Sogavare stood firm and came into this month's election as a favourite to win.

It would have made him the first Solomon Islands leader in history to serve a full term and win re-election.

An intense period of political horse-trading is still underway in Solomon Islands after no political party won enough seats at the April 17 election to form government on its own.

In what experts have labelled an "extraordinary process" where "acts of corruption" historically take place, the main political parties and their winning MPs are divided into camps in hotels and restaurants across the capital Honiara to try and build a governing coalition and select a prime minister.

Monday night's press conference with Mr Sogavare was held at the Cowboys Bar and Grill Restaurant in Honiara.

Insiders suggest Mr Sogavare, who was not considered a popular leader in Solomon Islands, was pushed out by his party, however, he rejected that notion saying he "felt great" handing over to a "very competent captain".

In Solomon Islands, 26 MPs are needed to form a government.

Mr Sogavare's party, the OUR Party, has 15 MPs in its coalition on Monday night, however, it claims to have as many as double that number.

The country's opposition group, led by Matthew Wale and the son of the country's first prime minister, Peter Kenilorea Jnr, claims to have 20 MPs.

There were 10 independent MPs elected.

Solomon Islands' MPs will head to parliament on Thursday to select the new prime minister, with history suggesting votes — and allegiances — could swing at the last minute.

In a noticeable change to Mr Sogavare's often assertive tone, Mr Manele, who political watchers consider more of a "statesman", said he just wished for a peaceful prime ministerial election.  

"I'm well aware of the challenges, and I know at times it can be lonely [as leader], but I am confident and confident in our policies and in the solidarity of our coalition," he said. 

"Our people have spoken and elected us, our first task is to elect a prime minister. May god bless Solomon Islands from shore to shore."  

• ABC Pacific