The latest opinion poll indicates sinking confidence in both of the main parties in the centre-left coalition.
The results suggest that public confidence in Prime Minister Antti Rinne's Social Democratic Party (SDP) was dropping quickly even before the latest turns and revelations surrounding the labour dispute at the state-owned postal firm.
Meanwhile, a change in leadership at the second-largest government partner, the Centre Party, has not improved its image or popularity. In September, Katri Kulmuni took over as Centre chair from the previous prime minister, Juha Sipilä. She also holds the posts of Minister of Economic Affairs and Deputy Prime Minister.
Halla-aho's populists leap to top of the chart
The Kantar TNS tracking poll was carried out in the first half of November, while the Posti strike was underway. The parties received the results last week, but Yle and other media did not obtain it until Monday.
It shows the SDP dropping to fourth place in terms of image. It was in first place before last spring's parliamentary election, which it won by a narrow margin.
Now it has been surpassed by the nationalist Finns Party, government partners the Greens and the other main opposition group, the conservative National Coalition Party (NCP).
The Finns Party, led by immigration hardliner Jussi Halla-aho, leapt from fifth place to the top of the chart, for the first time since 2010.
The Centre meanwhile slid to the bottom of the list, with the Greens the only government party to see an improvement in its public image. They remain in second place, as they were last spring.