The Social Democratic leader claims Lithuania's new government will make up its mind after evaluating the project's economic benefits.
"I don't think the disappointment is well-founded. I stick to the position that political decisions on important strategic issues should be based on economic logic," Butkevičius told the Žinių Radijas (News Radio) before leaving for Riga on Thursday.
The prime minister said he would inform Latvian leaders that based on a resolution adopted by the Lithuanian Seimas, the Lithuanian government is obliged "to submit draft laws on a further decision by May."
Butkevičius had promised the new government would make a decision by the middle of March.
The Social Democrats have been critical of the project authored by the previous rightist government.
In an advisory referendum held last October, voters overwhelmingly rejected nuclear energy. 34.09 percent voted in favor of constructing a nuclear power plant, and 62.69 percent voted against. Voter turnout was 52.58 percent.