The party of Fiji's incumbent Prime Minister and former coup leader, Frank Bainimarama, has narrowly won this week's election but his political opponents have indicated they may challenge the result due to concerns over the counting process.

Key points: Fiji's incumbent PM's party won 50.02 per cent of the vote

Fiji's incumbent PM's party won 50.02 per cent of the vote Opposition parties accused the electoral office of breaching law, challenging counting process

Opposition parties accused the electoral office of breaching law, challenging counting process International observers claim the elections were credible, but have raised some issues

Official results from Wednesday's national election showed that Mr Bainimarama's FijiFirst party has won 50.02 per cent of the vote — a drastic change from the party's landslide victory in the 2014 election when it secured around 60 per cent of the votes.

"Today, 18 November 2018, is truly a great day in our nation's history where the majority of you Fijians have emphatically voted and put your hand up to support the FijiFirst message of ongoing inclusive progress," Mr Bainimarama said in his victory statement, which he read to Fiji Broadcasting Corporation.

The SODELPA party led by Sitiveni Rabuka, Fiji's Prime Minister for much of the 1990s and the man who instigated two military coups in 1987, secured 39.85 per cent of the votes to become the largest opposition party.

Fiji's Prime Minister Frank Bainimarama at a polling place during the 2018 election. ( ABC News: Catherine Graue )

In recent days, however, several political parties, including SODELPA, have accused Fiji's Electoral Office of breaching the country's electoral laws by releasing provisional results earlier in the week.

This was only the second elections that Fijians voted in since Mr Bainimarama, then Fiji's military commander, took control over the sitting government in a coup 12 years ago.

Leaders of four of the six parties which contested this year's election have also made claims that some provisional results released publicly earlier in the week don't match up with their records, which were gathered by political party agents.

"We have this suspicion that … the results coming out from the FEO [Fiji Electoral Office's phone] app is actually not the right results," Professor Biman Prasad, leader of the National Federation party (NFP), told local media.

The NFP has won 7.38 per cent of the votes.

Four of the six parties which contested in this year's election have accused the electoral office of breaching the law. ( ABC News: Jarrod Fankhauser )

'The joint forces of opposition'

The four parties have raised their concerns with both Fiji's Electoral Commission and with international observers, who have been in Fiji to observe the elections at the invitation of the national Government.

"I'm not fully satisfied, that's why we brought up concerns with the multinational observers," Mr Rabuka told the ABC ahead of the final results being released.

"We may be calling for another one, because there are still issues we're not totally satisfied with.

Former prime minister Mahrendra Chaudry, currently the leader of the Fiji Labour Party, which failed to secure enough votes to be allocated any seats in parliament, also voiced concerns.

"We were cheated out of one election, we don't intend to be cheated out of a second," Mr Chaudry said.

But Fiji's supervisor of elections Mohammad Saneem hit back at the criticism.

"We don't have anything to hide," Mr Saneem said.

"I'm taking a very strong stand in this because it is not acceptable for political party leaders to come out with [their own] data to support their claims of improper election results recording."

Mr Saneem claimed it was unfortunate that the opposition parties have chosen to question the official results for what he described as "the purpose of achieving some political mileage".

This was the second elections that Fijians voted in since the coup 12 years ago. ( ABC News: Catherine Graue )

"Despite the joint forces of opposition that started their campaign based on lies, hate and fear against us four years ago, we have triumphed," Mr Bainimarama said in his victory statement.

"Because you the people of Fiji … have rejected the divisive table thumping politics of the old Fiji and instead believed and dreamt with us of a modern Fijian nation-state where no one is left behind."

'A significant step towards democracy'

International observers concluded on Friday, when releasing their interim report, that the electoral processes "to date have been transparent and credible" and that the people of Fiji were able to "vote freely".

The Multinational Observer Group, co-led by Australia, congratulated the people of Fiji for taking a "significant step" towards embedding democracy.

The Australian co-lead, Liberal MP Jane Prentice, said it was clear there remains a lack of trust in the Fiji electoral system and broader governance, given the political turmoil seen in Fiji since 2006.

As the Commander of Fiji's military, Mr Bainimarama took control of the government, promising to "clean out" corruption.

He promised to hold elections in 2010 but they were postponed until 2014, during which his interim-government ruled by decree, with heavy restrictions on media freedoms and civil society.

International observers concluded that the electoral process was free and credible. ( ABC News: Catherine Graue )

"There was definitely prior to 2014 a level of perhaps distrust in the community... and it takes some time to regain that trust," Ms Prentice said.

"We're confident that this election was transparent, and it was free."

But the observers have raised several issues in their interim report, including the use of state resources by the incumbent government during the campaign period.

"Fiji appears to have few protocols in place to guide the Government...on appropriate conduct during the official campaign to ensure public confidence in a level electoral playing field," the interim report stated.

A final report will now be finalised, with recommendations to be handed to the new Fiji Government.