New Democracy officials said after the first exit poll showing the party's lead that they would wait for official results.
In statements to the press, they said after the end of voting at 19:00 on Sunday, "We are awaiting the official results, but data shows that we have succeeded in getting what we asked for: a clear victory with a wide margin."
Main opposition SYRIZA-Progressive Alliance said it would wait for the official election results on Sunday, after exit polls showed New Democracy leading by a wide margin.
"Let us wait until we see the first true results, because we are experienced in elections and know that true results could differ," Syriza sources said.
"The picture we have is that 1 in 3 voters did not answer, so let us be patient to see the first true results," they added.
PASOK-KINAL party officials welcomed the results of exit polls that were released by television stations a few minutes after polling stations closed at 19:00 on Sunday.
The party "increases its percentage by 40%, which confirms that the target for a strong double-digit percentage is almost achieved," they said.
Furthermore, they underlined that "PASOK-KINAL's strategic target to make a dynamic return - and become a leading progressive pillar in the political scene - is confirmed."
A response by party leader Nikos Androulakis is expected when the official results are issued.