Under the government order amending the existing quarantine conditions, people must wear "means of protection (facemasks, respirators or others) to cover their nose and mouth".
Up until now, it has been only recommended to do so.
"The decision on mandatory wear of personal protective equipment – masks, respirators and other similar items covering faces – was made today," Prime Minister Saulius Skvernelis told a press conference following a Cabinet sitting on Wednesday.
"Let's not understand that absolutely. If you are walking alone in the forest, that's one regime, but if a person is approaching and there's a possibility of contact, such protection must definitely be worn," he added.
The rules were tightened to make people accustomed to wearing personal protective equipment, the prime minister said.
"We don’t want to punish people but we want to make people accustomed to doing that, especially as we speak about trading venues that are operating now or might be opened in the future, and also certain services. We need that skill of protecting oneself to develop," Skvernelis said.
"The supply of medical masks is emerging in the country. We are giving several days for people to buy them," the prime minister said.
The head of government also asked officers not to rush into punishing people without masks but to carefully look into a specific situation.
"I hope officers will be very polite and principled when ensuring compliance and will not rush into issuing fines. That's not the goal or requirement. We just need to consider every person and situation individually, wisely and responsibly and take other measures defined by the law only in exceptional cases," Skvernelis said.
"But if people are warned but still refuse to wear a mask, then officers have the right to apply sanctions," he said.
The Seimas of Lithuania earlier increased fines for people flouting quarantine requirement and they now face fines ranging from 500 to 1,000 euros. Executives of legal entities or other responsible person will face fines ranging from 1,500 to 6,000 euros.