The five-yearly elections, in which 73.5 million to 79 million registered voters will also choose representatives for local councils, are one of the few nods to democratic practice in the tightly controlled one-party state.
The most powerful positions are decided by Communist senior officials ahead of the vote.
Almost 93 per cent of the 864 candidates running for the national parliament are Communist Party members, while 7.5 per cent are independents, according to the national election council.
The proportion of independents is down from 8.5 per cent in 2021, leaving no doubt the party will maintain its overwhelming dominance in the assembly.
In the current legislature, the Communist Party, which has ruled the country unopposed for decades, holds 97 per cent of the seats.
The unicameral parliament has virtually no power to challenge the party's key decisions, including on personnel, but it has occasionally amended proposed laws.
Voters interviewed by Reuters at polling stations were largely upbeat, expressing hope their representatives would continue modernising Vietnam, whose booming economy is undergoing major reforms introduced by top leader To Lam.
"I hope the representatives elected will guide young people in the right direction and introduce policies that better support youth," first-time voter Phan Nam Khanh, 22, said.
Parliament chairman Tran Thanh Man told local media the results of Sunday's election would be announced on March 23.
Turnout has exceeded 99 per cent in each of the past seven parliamentary elections, according to the state news agency.
The opening plenary session is scheduled for early April, when lawmakers are expected to approve the state's top leaders previously nominated by the party, including the president and the prime minister.
The party confirmed Lam as its general secretary - the nation's most powerful position - during its five-yearly congress in January, when it also selected the 19 members of the politburo, its top decision-making body.
Party officials are expected to formally announce their nominees for state leadership before parliament's opening session, with Lam's elevation to the presidency widely viewed as a formality.
The move would allow the former head of public security to hold both powerful roles for five years, aligning Vietnam's political structure more closely with that of neighbouring China, where Xi Jinping also holds both positions.
Candidates include business leaders and party members Nguyen Thanh Tung, head of Vietcombank, Vietnam's largest bank by market capitalisation, and Le Hong Minh, chairman of technology firm VNG, which owns the country's most popular messaging app Zalo.
