The ruling conservative Law and Justice (PiS) party won 46.5 percent of the vote in an election held in the central town of Wieruszów at the weekend to measure voter sentiment ahead of the real ballot.
Meanwhile, the largest opposition bloc, the Civic Coalition, led by the Civic Platform (PO) party, was runner-up with 23.49 percent support, Poland’s PAP news agency reported.
The Civic Platform headed the country's previous two governments from 2007 to 2015.
A block of three leftist groupings led by the post-communist Democratic Left Alliance (SLD) was third with 13.08 percent.
The Polish Coalition of the rural-based Polish People’s Party (PSL) and the anti-establishment Kukiz’15 grouping finished fourth with 7.86 percent in the test election in Wieruszów on Sunday.
The right-wing nationalist Confederation group, with 7.02 percent, also crossed the 5-percent voter support threshold that Polish parties need to clear to enter parliament.
Residents in Wieruszów and the surrounding area were asked to cast their votes in 12 polling stations to support one of the groups that will be contesting the real parliamentary elections next Sunday.
Voters were asked to state their support for a party, not specific candidates.
In total, almost 2,000 votes were cast in the mock election, with turnout at around 13 percent, Poland’s PAP news agency reported.
Sunday’s mock election in Wieruszów drew from a tradition that was started in 1997. This district of 14,000 residents is considered to be a good model of voter preferences nationwide.
Mock elections held in the town over the years have usually mirrored the returns later in national parliamentary, presidential and European elections, the PAP news agency reported, citing a local official, Marek Patyk.
The difference between the mock and real results has usually been within the margin of statistical error, according to the news agency.
Poles will head to the ballot box to vote in parliamentary elections on October 13.
They will elect 460 MPs and 100 senators for a four-year term.
With election day less a week away, the country’s ruling conservatives appear to be running ahead of an opposition divided into separate blocs, according to the latest polls.
The governing conservative Law and Justice (PiS) party, allied with two smaller groupings in a United Right coalition, is seeking a second term in power after a landslide win in 2015.
Seventy-seven percent of respondents to a recent survey said they intended to vote in the upcoming ballot.