Sierra Leone's main opposition has said it will boycott parliament and local councils unless its concerns about the recent elections are addressed.The Sierra Leone People's Party, which won 40% of parliamentary seats, alleges this month's polls were fraudulent.Their presidential candidate, ex-military ruler Julius Maada Bio, also lost to incumbent Ernest Bai Koroma.International observers said the poll, the third since the civil war, was conducted peacefully and transparently. ArrestsThe SLPP alleges that some ballot boxes are stuffed with pre-marked ballots.But the electoral commission, which released the presidential election results on Friday and parliamentary and local council results on Monday, has said it found no evidence of "over voting".The BBC's Umaru Fofana in Freetown says the law states that an MP who does not show up in the house for about three months forfeits their seat.In the run-up to the elections there were clashes between rival party supporters in the capital, Freetown.After the presidential results were announced on Friday, about seven SLPP supporters were arrested in the eastern town of Kenema because police feared riots.The SLPP also demanded that some of its supporters be released from police custody, and all charges against them dropped.The SLPP controls nine out of the West African nation's 19 local councils.President Koroma, of the ruling All People's Congress, won a second and final term in office with almost 59% of votes cast.The vote was the first post-war election Sierra Leone had organised itself - the other two held since the war ended in 2002 were run by the United Nations.Since the end of the 11-year war, in which an estimated 50,000 people were killed, Sierra Leone has made progress towards reconciliation.However, it remains one of the poorest countries in Africa with a large number of the population of about six million living on less than $1.25 (80p) a day.