Slovakia's Finance Minister Peter Kazimir on Sunday warned that Greece's 'No' referendum result opened the door to the country's departure from the eurozone, becoming the first European minister since the crucial vote to raise the prospect of a "Grexit".
"The nightmare of the 'euro-architects' that a country could leave the club seems like a realistic scenario after Greece voted 'No' today," Kazimir tweeted after results showed Greek voters decisively rejecting creditors' bailout terms in the landmark referendum.
Poorer eastern eurozone members and non-member Poland voiced deep dismay at the 'No' outcome, but some held out the prospect of further talks.
"Greece exiting the eurozone will not mean anything, Slovakia will not be harmed as a result of Greece and its decision to stay or leave the single currency union," Slovakia's leftist Prime Minister Robert Fico said earlier Sunday.
"Slovaks will not lose one euro because of the Greeks, as we did not give any cash, only our guarantees," he added.
Lithuania's President Dalia Grybauskaite said the Greek vote has "further complicated the situation", and accused the leftist government in Athens of failing to tell voters the truth.
"The Greek government, instead of telling the truth to its people about the real outcome of such decision, agitated to vote against reforms which are necessary to stabilise the financial situation," she added.
"Does not look good for the future of Greek people...", Estonian Prime Minister Taavi Roivas tweeted.
Latvian PM Laidmota Straujuma tweeted that a "Greek 'No' in the referendum will make any further negotiations very difficult."
"As we have said before, Europe keeps the door open for negotiations if the Greeks are willing to return," Straujuma's spokeswoman Aiva Rozenberga later told AFP.
A nation of 5.4 million, Slovakia became the second formerly communist state to join the eurozone in 2009.
Having broken free from the crumbling Soviet Union in 1990-91, tiny Baltic states Estonia and Latvia joined the eurozone in 2011 and 2014 respectively, followed by neighbour Lithuania this January.
Poland, which does not belong to the 19-member eurozone, also raised the spectre of Greece crashing out of the euro.
The Greeks "said 'No' to (European) aid, so they also said no to the eurozone. This will probably be a new stage towards (Athens) leaving the eurozone," Poland's Prime Minister Ewa Kopacz told Poland's TVP public broadcaster.
Central European heavyweight Poland is obligated to join the euro under the terms of its 2004 EU entry, but Warsaw insists it will only do so after the debt crisis is resolved.
Nearly 70 percent of Poles said they opposed joining the bloc, according to recent surveys.