The parliamentary polls, officially recognised only by Ankara, are widely seen as a referendum on veteran Turkish Cypriot leader Rauf Denktash and his rejection of a UN plan to reunify the island after nearly three decades.
"This is not going to be a race between parties... It's going to be a referendum between those who want a settlement and those who don't," said prominent local businessman Fikri Toros.
The result could determine whether Turkish Cypriots cast off their internationally imposed isolation and join the EU next year in a federation with their Greek-speaking compatriots, or hunker down in the hope of an eventual two-state solution.
The EU has sent a clear message to Turkey that its chances of starting full accession talks with Brussels after a review of reforms late next year will be seriously damaged if Ankara fails to push the Turkish Cypriots to a prompt deal.
With no independent opinion polls the result is hard to predict, although many local observers suggest the opposition parties have a good chance of shaking the coalition government's current hold on two-thirds of parliamentary seats.
Denktash's position as president of the enclave of 200,000 people, which survives international sanctions with an economic lifeline and military backing from Turkey, is not up for grabs.
But the three main anti-Denktash parties say they will replace him as negotiator and push urgently for a settlement that could take the north into the EU as part of a reunited Cyprus, rather than leaving it in the cold when the Greek Cypriot government joins the affluent bloc next May.
"There is a way to the EU with our head held high"
Turkish Cypriot President Rauf Denktash
Talks on a UN blueprint for reunification, envisaging a loose federal state with broad autonomy for the two communities, collapsed in March when Denktash flatly rejected it.
"There is a way to the EU with our head held high. That is once our status has been made certain," Turkey's Anatolian news agency quoted Denktash as saying on Saturday in a final show of support to the two government parties backing him.
"Those who do not accept our status today will crush us into dust tomorrow inside the EU."
Just over 140,000 people are eligible to vote for the 50-seat legislature, based in a former cigarette factory in the northern part of Nicosia, Europe's last divided capital.
The three main opposition parties
say they will oust Denktash
Polls open at 0600 GMT, with initial results expected by 17:00 and final provisional results by 22:00.
Only Turkey has sent official observers but non-governmental groups from several countries, including Britain and Norway, are present and Western diplomats are keeping an unofficial watch.
The opposition accuses the government of trying to sway the vote by rushing through citizenship for thousands of mainland Turks who have settled since 1974, when Turkey invaded after a Greek Cypriot coup backed by the junta then ruling Greece.
The government says only genuine claims were approved. The number of mainlanders on the electoral roll remains secret.
Many mainland Turks fear they will be thrown out of Cyprus if the island is reunited, while Denktash and his allies say a single Cypriot state would erode Turkish Cypriot rights.
But many Turkish Cypriots are tired of isolation, and are hungry for the economic opportunities presented by the EU.