Armed police fanned out across the kingdom on Friday monitoring schools and other public buildings being used as polling stations.
Political parties in the tiny landlocked mountain kingdom engulfed by South Africa have been banned since 1973.
Candidates contesting seats in parliament can only stand as independents under the existing system.
'Mockery of democracy'
Banned political parties and civil society groups have been fighting for multi-party elections and the abolition of the monarchy.
"How these elections are called democracy is beyond me," said Mario Masuku, the leader of the People's United Democratic Movement, one of Swaziland's banned political parties.
"The country's political systems makes it a mockery of democracy in the region. In Swaziland there are no elections just selections of people who dance to the king's tune."
Foreign observers are bing allowed to monitor the elections for the first time.
"The vote will be free and fair. We are confident that the process will go on without any disturbances," Mzwandile Fakudze, the deputy chairman of Swaziland's election and boundaries commission, said.
The poll is the first time elections are being held under the amended constitution, which came into force in 2006 and allows for freedom of association but still maintains the ban on political parties.
Many voters queued up at the polling stations before they opened.
About 300 mostly elderly Swazis, many wearing traditional attire, were lined up outside a booth in the capital Mbabane's Zulwini station waiting patiently to vote.
Candidates in the elections are vying for 55 seats in the national assembly while King Mswati III, Swaziland's monarch, nominates 10 others to the house which picks 10 representatives for the senate.
The king also selects 20 others to the upper chamber, appoints a prime minister and selects a number of other top government officials.
Some voters have only registered to vote because a voting card is essential to gaining access to jobs.
"I have been told that when you do not have a voter card it is impossible to access things like scholarships and government jobs for you or your kids," said Nomusa Nhleko, a 32-year-old voter who said she had never participated in elections before.