The Electoral Commission of Queensland declared the result on the strength of Mr Martin's primary vote on Tuesday, without needing to count first preferences.

He took home 56.58 per cent of the primary vote against the Liberal National Party's Jim Bellos who polled 32.67 per cent in Saturday's by-election.

Candidates from the Greens, the Informed Medical Options Party and the Animal Justice Party garnered less the 11 per cent of the primary vote.

Mr Martin, a former Labor staffer for Mr Pegg, will succeed the popular local MP who died of cancer just shy of his 41st birthday on June 10, ending his six-year parliamentary stint.

Labor had already claimed victory on Saturday night with 56 per cent of the vote counted..

"I want to thank all the Stretton community for supporting me to be the next member for Stretton," Mr Martin said in a statement on the night.

"I will work everyday to continue the legacy of my friend Duncan Pegg who lost his battle to cancer too young."

Mr Martin said that as part of Annastacia Palaszczuk's Labor team in government he would deliver for Stretton, from road upgrades to investment in local schools.

"The hard work starts today."

In a statement Mr Bellos congratulated Mr Martin and said that while the result was not what he had hoped for the LNP had increased its vote in the seat.

"The cause of the by-election was tragic and James has large shoes to fill.

"We will be watching carefully to make sure that our area doesn't miss out on its fair share," Mr Bellos said.

The Greens nominated Andrea Wildin, Suzanne Clarke ran for the Animal Justice Party and Jasmine Melhop was on the ballot for Informed Medical Options.

More than 18,000 of the almost 34,000 constituents voted in person. Some 10,200 voted on election day, while 7800 chose to vote early.

Postal votes will only be returned by August 3.

Labor's Stephen Robertson held Stretton from 2009 until 2012 and also its predecessor seat of Sunnybank from 1992 until 2009.

Australian Associated Press