Sylwester Marciniak made the declaration in an interview with state news agency PAP, published on Thursday morning.
The head of the State Electoral Commission (PKW) said: “I would like the results to be unveiled before noon on Tuesday at the latest.”
He added that the results could be known on Tuesday morning, or possibly overnight into Tuesday.
Marciniak told reporters that vote counting “must be done smoothly, but above all in a credible way.”
He noted that some 30 million Poles were eligible to vote, plus some 600,000 who had declared they would cast their ballots abroad.
Marciniak said he hoped that voter turnout would be “the highest since 1989,” the PAP news agency reported.
He added that "relevant laws and procedures" ensured the elections would be free and fair, while any irregularities “will be dealt with immediately.”
He emphasised that the ballot would be observed by election monitors.
Marciniak urged everyone “to exercise restraint” and “have respect for each other” in the final days of the election campaign, the PAP news agency reported.
Poland to elect new parliament on October 15
Poles will head to the ballot box to vote in parliamentary elections on Sunday. They will elect 460 MPs and 100 senators for a four-year term.
Seeking a third term in power, the governing conservative Law and Justice (PiS) party appears to be running ahead of an opposition divided into separate blocs.
Poles to vote in referendum
In August, Poland's lawmakers approved a plan to combine parliamentary elections with a nationwide referendum asking Poles whether their country should accept migrants from the Middle East and Africa, whether state companies can be sold to foreign buyers, whether the retirement age should be increased, and whether a wall on Poland's border with Belarus should be dismantled.
The ruling conservatives have encouraged people to cast their ballots in the referendum, while the opposition has asked voters to boycott it, saying the referendum questions are worded in a biased way and contain misleading information designed to boost support for the government.
(pm/gs)
Source: PAP, PKW