With 94 percent of voting districts counted, the Left Party, Social Democrats, Green Party and Centre Party are projected to secure 176 seats, while the Liberals, Christian Democrats, Moderates and Sweden Democrats appear to take 173 seats.
Overnight, the figures fluctuated between that distribution and a narrower 175-174 margin for the opposition, but the numbers appeared to stabilise during the early morning hours.
AS IT HAPPENED: The Local's live blog from Election Night
However, votes from late postal and overseas voters will be counted later in the week during the Wednesday count, meaning it could take some time before the final distribution of seats is clear.
And then remains the issue of forming a government, which could take weeks or even months.
Here are the votes as of 9.50am on Monday:
Social Democrats: 28.1 percent (-2.3)
Centre Party: 7.1 percent (+0.3)
Christian Democrats: 6.2 percent (+0.9)
Liberals: 5.4 percent (+0.8)
Green Party: 6.1 percent (+1.0)
Moderates: 19.9 percent (+0.8)
Sweden Democrats: 17.6 percent (-3.0)
Left Party: 8.2 percent (+1.5)
Other parties: 1.6 percent (+/-0)