Colombians go to the polls on Sunday in congressional elections that will see former members of the Farc guerilla group take part for the first time.
The ex-rebels, now known as the Revolutionary Alternative Common Force (also Farc), were given 10 congressional seats as part of a historic peace deal signed in 2016.
But opinion polls give the left-wing group little chance of making gains.
The vote is being viewed as a test ahead of May's presidential elections.
Analysts expect the composition of Colombia's Congress to remain largely the same, with conservative parties who oppose the peace agreement hoping to win an absolute majority.
The Centro Democratico party, led by former president and current senator Alvaro Uribe, is predicted to win the most seats.
Mr Uribe's party has fiercely opposed the peace deal and its members include some of the Farc's most vocal enemies.
The peace agreement has polarised the country because Farc rebels fought the government for more than 50 years and more than 260,000 people were killed in the conflict.
Under the terms of the 2016 deal, the Farc are guaranteed 10 seats in the legislature as long as it campaigns for them.
The BBC's Katy Watson, who is in Bogotá, says that many Colombians feel it is too soon to see former rebels in positions of power and say they should have been punished for their crimes.
They have faced hostility on the campaign trial, and the group's leader Rodrigo Londoño was pelted with eggs and tomatoes while out campaigning last month.
Farc's candidates have acknowledged that they need to convince voters they have changed, but say their involvement in elections represents a fresh start for the country.
Sunday's vote will also include party primaries ahead of presidential elections in May.
But Mr Londoño – better known by his nom de guerre, "Timochenko" – will not be standing, after he withdrew from the presidential race because of ill-health.
He is recovering after undergoing heart surgery in a Bogotá clinic on Wednesday.
President Juan Manuel Santos won re-election in June 2014, gaining what he presented as an endorsement of his efforts to end the rebel insurgency.
He staked his reputation on securing a peace deal with the Farc and launched peace talks with the group two years after taking office in 2010.