The poll, commissioned by DELFI and conducted by Spinter Tyrimai on May 19-26, asked respondents who they thought was the best candidate to head the Lithuanian government.
Butkevičius, the incumbent, continues to top the popularity rankings, with more than one in five respondents naming him as their top choice.
However, Butkevičius' 22.4% represents a dramatic 5-point drop month-on-month. In April, 27.4% said Butkevičius was the best candidate for the prime ministerial post. Last November, his rating peaked at 32.9%.
"[The drop] exceeds the margin of error and indicates that something is happening, it is not just fluctuation," says political scientist Ainė Ramonaitė of Vilnius University.
She speculates that the decline of Butkevičius' ratings might have to do with a series of relatively small scandals that hit the Sociald Democratic Party over the last year.
"It was clear then that the party is incapable of reacting swiftly to the changing situation. This could reflect the voters' overall disappointment," according to Ramonaitė.
Still, Butkevičius remains the most popular candidate for the post he currently holds. The next most popular choice is Gitanas Nausėda, economist at SEB Bank, who is thought of as the best candidate to head the government by 6.8% of respondents, up from 3.3% last month.
MEP Rolandas Paksas, leader of the Order and Justice party, is third with 4.8%, followed by former Interior Minister Saulius Skvernelis. Economist Ingrida Šimonytė, former Minister of Finance, is favoured by 4.3%.
Gabrielius Landsbergis, leader of the conservative Homeland Union-Lithuanian Christian Democrats, has a rating of 4.2%, slightly up from April's 3.9%.
The poll did not rank the former leader of the Liberal Movement, Eligijus Masiulis, who stepped down following bribe taking allegations last month.
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