Sri Lanka's opposition has vowed to deny the ruling coalition a two-thirds majority in this week's parliamentary elections, as candidates wrap up their campaigns.
A majority of the 225-seat legislature would allow Mahinda Rajapaksa, the already powerful president, to bring major constitutional changes.
Rajapaksa, who won a landslide re-election in January, has said he expects his United People's Freedom Alliance (UPFA) to achieve the majority at Thursday's polls.
He has not said what changes he would make were the UPFA to win a majority.
Campaigning ended on Monday.
Rajapaksa well placed
Analysts expect the UPFA to win the poll after Rajapaksa's January victory, the defeat of the Liberation Tigers of Tamil Eelam (LTTE) in May, and predicted economic growth of 6.5 per cent this year.
The country had suffered a 25-year civil war until the military's victory over the LTTE.
"It's not healthy for the country and will be a deadly attack on democracy to have the executive powers and two-thirds in parliament with one party. They will abuse the extensive powers," said Vijitha Herath, secretary for the Democratic National Alliance (DNA), the second largest opposition group.
Rajapaksa won the presidential election in January after beating Sarath Fonseka - the general who led the military's victory over the LTTE - by 58 to 40 per cent.
Fonseka was subsequently arrested by the military and remains in custody, charged with being involved in politics while a member of the army. He is still running for parliament.
Campaigning has been quiet compared to that of the presidential poll.
However, assailants sprayed campaigners with bullets, killing one person, on Monday.
Western governments, rights groups and the opposition have accused the government of violating human rights, intimidation and not prosecuting attacks on journalists and political oppostion.
The government has said that the accusations are incorrect and the opposition is attempting to gain favour with Western powers.