The SDS is in the lead with 13.4%, down 1.8 points on the month before, with the SD trailing with 11.7%, a drop of over one percentage point.
The coalition Liberal Democrats (LDS) and Pensioners' Party (DeSUS), on the other hand, made significant gains.
The LDS, which had been bleeding support after its leader got embroiled in a series of scandals, was up a point to 4.2%. DeSUS, meanwhile, more than doubled its rating to 4.2%.
The opposition National Party (SNS) and People's Party (SLS) also improved their ratings, the former by 1.4 points to 3.7% and the latter by 1.5 points to 2.8%.
The biggest loser this month is the coalition Zares, which saw its ratings halved to 1.1%.
Zares has been in the spotlight in the recent weeks after infighting led to the resignation Matej Lahovnik as economy minister and MP.
Almost a third of respondents were undecided and over a quarter would not go to the polls.
Respondents were also asked whether Slovenia needs to change its pension system and the majority, 60.7%, were in favour.
However, the poll also shows a generational gap: the young and educated were overwhelmingly in favour of reform whereas pensioners or those nearing retirement age were against.
