Government officials say Lithuania could in the future help Belarus to import gas, too, if Minsk wanted to reduce its dependence on Moscow.
The Breiviken tanker is expected to deliver a crude oil cargo to Klaipeda this week, Klaipedos Nafta, the operator of the Klaipeda oil terminal, has confirmed.
From the Lithuanian port, the crude will be transported to Belarus by rail.
Giedrius Sabaliauskas, Klaipedos Nafta's oil business director, told BNS that dialogue with Belarusian customers on oil product exports and crude imports was ongoing.
"At the moment, we have no other inquiries from Belarus regarding crude oil imports, but as we have already said, today we estimate that we could handle up to 3 million tons of crude via the terminal," he said.
Mantas Dubauskas, a spokesman for Lietuvos Gelezinkeliai (Lithuanian Railways), said the state railway company "is constantly monitoring the market situation and seeking to offer competitive solutions to customers".
Reuters reported on Monday that Belarus' oil company BNK would import the crude from Norway's Johan Sverdrup via Klaipeda.
"We expect the shipment, and will continue further negotiations then," Belarus' state company Belneftekhim that controls BNK told the news agency.
"Some 80,000 tons of Johan Sverdrup oil will be supplied by rail to Belarus' Naftan refinery," according to the news report.
Russia suspended oil supplies to Belarus' refineries on January 1, but partially restored them several days later, after Moscow and Minsk failed to agree on the terms of supplies for 2020.
Belarus' authorities said last week they had sent oil import proposals to the Baltic countries, Poland, Ukraine, Kazakhstan and Azerbaijan.
Foreign Minister Linas Linkevicius says Lithuania can offer Belarus an alternative to both oil and gas imports from Russia.
The minister plans to discuss energy supply issues during his visit to Minsk in early February.
"We are interested in Belarus diversifying its energy supply sources, and one such example is the use of the Klaipeda port and Lithuanian railways," Linkevicius told BNS on Monday evening.
"If there was an interest, gas supply issues could also be discussed. We'll be able to discuss these issues during my visit to Minsk, alongside other topical issues on our agenda," he added.