"Many services and a part of non-food vendors and smaller shops reopened last Monday (February 15). And we saw a sharp increase in people's mobility from the very first day," she told the Ziniu Radijas radio station.
People's mobility has now returned to pre-holiday levels and the increasing number of contacts allows the virus to spread, according to Simonyte.
"Mobility data suggest that these contacts have really intensified," she noted.
Lithuania reported on Wednesday evening eleven new cases of the British coronavirus variant, bringing the total number of known cases in the country to twelve.
Simonyte said the spread of the mutation could also be a reason why the country's daily coronavirus count had stopped falling.
More data is needed to see if the UK variant is present only in certain areas or is spreading across the country, according to the prime minister.
"The main question now probably is in which direction the trajectory is going: whether we'll manage to keep it tight but stable and maybe start reducing it through testing, or we'll see some rebound again, which, of course, wouldn't be very good news," she said.
The prime minister said she was pinning hopes for further loosening restrictions on plans to increase the scope of coronavirus testing, including antigen and pool testing.
The government on Wednesday extended the coronavirus lockdown for another month, until April, and the ban on non-essential travel between municipalities until March 15, but lifted restrictions for travelling between the country's six major cities – Alytus, Kaunas, Klaipeda, Panevezys, Siauliai and Vilnius – and their surrounding districts.
As of Thursday, it is not mandatory to wear facemasks in open spaces if a distance of at least two meters from other people is maintain. The indoor mask-wearing rules remain unchanged.
Simonyte said on Wednesday that further lockdown easing steps, such as reopening of cultural facilities and some larger shops, would depend on the epidemiological situation.