Ethiopia's ruling party and its allies have won a landslide victory in the country's parliamentary elections, based on preliminary results from the weekend polls, the country's electoral board has said.

In results announced by the board on Wednesday, the EPRDF and its allies have so far won all of 442 seats declared, leaving the opposition empty-handed.

The results of voting in the remaining 105 seats are yet to be announced.

The election was marred by allegations by the EPRDF's political opponents that their supporters were harassed.

The charges of abuse were dismissed by Hailemariam Desalegn, the prime minister and leader of the Ethiopian People's Revolutionary Democratic Front (EPRDF), which has been in power for almost 25 years.

The party was widely expected to sweep the vote.

It was not an election, it was an organised armed robbery.

Merera Gudina, chairman of the Oromo Federalist Congress

The electoral board said turnout exceeded 90 percent.

Lines could be seen forming in front of polling stations on Sunday in what appeared to be a relatively high turn-out. More than 36.8 million voters had registered for the elections, a 26 per cent increase compared to 2010.

Most of the voters interviewed by Al Jazeera indicated they had voted for the ruling party.

But voters also reported that on Sunday afternoon, ruling party members were conducting door-to-door campaigns to ensure voters attended.

"In my area, the EPRDF supporters went from house to house. They knew if you had voted or not," said a voter who refused to give his name.

The lead-up to the elections was marred by allegations by the leading opposition parties over intimidation of opposition members as well as obstruction of the campaigning and voter registration process.

MEDREK and the Blue Party, the two leading opposition parties running, both reported irregularities on the day of voting, including obstruction of opposition party observers to enter polling stations.

"It was not an election, it was an organised armed robbery," Merera Gudina, chairman of the Oromo Federalist Congress, who ran under MEDREK's ticket, told Al Jazeera on Tuesday evening.

Documenting violations

Gudina reported that out of 71 ballot boxes in a constituency in Ambo, an area known for anti-government protests, MEDREK party observers were only able to sign off on 20.

Gudina said on Tuesday that the party was in the process of documenting violations, but that no complaints had been filed with the electoral board so far.

"This time around we are fed up. Last time we hired lawyers, but the election board said we didn't have any evidence," Gudina, who accuses the electoral board of political bias, told Al Jazeera.

Talk to Al Jazeera: Hailemariam Desalegn

In its preliminary report, the African Union's election observation mission said on Tuesday that the elections were "calm, peaceful and credible," but reaffirmed several concerns raised by opposition parties.

In one of five polling stations visited, AU observers noted campaigning inside polling stations, further stating that officials failed to demonstrate the ballot boxes were empty before voting began. 

The EPRDF has governed since it overthrew the Derg regime in 1991 and currently controls all but one seat in parliament.

Although 58 political parties contested the vote, most were said to be weak or allied with the ruling party.

The ruling party has been credited with double-digit economic growth over the past five years, but critics say there has been little progress in creating an open political environment necessary for elections.

"The 2015 general election has been successfully completed, with high participation of our citizens who committed themselves to the development of democracy," said Merga Bekana, the chairman of Ethiopia's electoral board.

The final results will be announced on June 22.

Source: Al Jazeera And Reuters