Thiruvananthapuram, Jun 27 (IANS): Voters turned up in large numbers on Saturday to cast their ballot in the by-election for Kerala assembly constituency Aruvikara, an official said.

Voters queued up much before the start of polling at 7 a.m and after three hours of polling 21 percent of the electorate had exercised their franchise.

The by-poll was necessitated following the death of sitting member and assembly speaker G. Karthikeyan in March. He had represented the constituency for 24 years.

There are a total of 16 candidates in the fray, and there are a total of 184,210 voters -- up from 164,884 in 2011, when Karthikeyan won with a margin of over 10,000 votes.

The ruling Congress has fielded Karthikeyan's 31-year-old son K.A. Sabarinathan, while the Communist Party of India-Marxist has nominated 67-year-old former speaker and minister M. Vijayakumar and the Bharatiya Janata Party has pitted its regular warhorse, O. Rajagopal, 85, in the fray.

On Saturday, all three candidates expressed confidence of winning the poll.

Sabarinathan said his biggest advantage is that Aruvikara electorate has been an extended family for him, while Vijayakumar said Keralites all over the world were viewing this election and the electorate is waiting to give a fitting lesson to the Oommen Chandy government.

Rajagopal said for the past five decades, the people of Kerala had just two options, either the Congress-led front or a CPI-M led government. He said the BJP has now emerged as the third alternative and people will definitely vote for a change.

Saturday's election will see the photo of candidates affixed on the Electronic Voting Machines (EVMs) for the first time in a bid to eliminate confusion among voters.