Over a decade since Tunisia's popular revolution unseated dictator Zine El Abidine Ben Ali, opposition parties have urged a boycott of the Saturday vote, which they say is part of a "coup" against the only democracy to have emerged from the 2011 Arab Spring uprisings.
Saied's new system essentially does away with political parties and electoral lists, meaning candidates will be elected as individuals with no declared affiliation.
Almost all the country's political parties, including Ennahdha, have said they will boycott the vote, labelling Saied's moves a "coup."
Few of the country's nine million registered voters are expected to turn out.
The election for the new 161-seat assembly comes after President Saied froze the previous legislature on July 25 last year, following months of political crisis exacerbated by the coronavirus pandemic.
The previous legislature had far-reaching powers, in the mixed presidential-parliamentary system enshrined in the North African country's post-revolution constitution.
He later dissolved the parliament, which had long been dominated by his nemesis the Islamist-inspired Ennahdha party.
Saied on Wednesday defended his decision, saying that the "Tunisian people, wherever I went, were all asking to dissolve the parliament".
Last July, Saied used a widely shunned referendum to push through a new constitution, stripping parliament of any real clout and giving his own office almost unlimited powers.
Saied on Wednesday defended his decision, saying that the "Tunisian people, wherever I went, were all asking to dissolve the parliament."
"The country was on the brink of civil war," he told US Secretary of State Antony Blinken in Washington.
The legal expert who oversaw its drafting said the version Saied published had been changed in a way that could lead to a "dictatorial regime". Saied later published a slightly amended draft.
Analyst Hamadi Redissi said the aim of Saturday's polls was "to complete the process that started on July 25" last year.
The resulting parliament "won't have many powers -- it won't be able to appoint a government or censure it, except under draconian conditions that are almost impossible to meet."
The vote aims "to increase the legitimacy of the presidency", Redissi said, adding that the result would be "a rump parliament without any powers".
The powerful UGTT trade union federation, which did not openly oppose the initial power grab, has called the poll meaningless.
Most of the 1,058 Saturday election candidates are unknowns.
Several young people told AFP they had little interest in the election or desire to know more about the candidates.
And Marwa Ben Miled, a 53-year-old shopkeeper, told AFP the country was "going from bad to worse".
"What happens on the political scene doesn't interest me anymore," she said. "I don't trust anyone."