But members of Prime Minister Benjamin Netanyahu's governing coalition have called for the opening session of the new parliament to be postponed and raised the possibility of annulling the election results.
Dean Livne, the acting director general of the Central Elections Committee, said that there was no indication that Arab parties had obtained votes unlawfully.
Police Commissioner Daniel Levy said every complaint received in connection with the election would be investigated thoroughly and impartially.
Should there be any suspicion of criminal offences, police would act decisively to uncover the truth and bring those involved to justice, he said.
Arab parties nearly doubled their seat count from the 2022 parliamentary elections in Tuesday's vote, winning a total of 19 of the 120 seats in the Knesset, according to the current tally of votes.
Neither Netanyahu's conservative Likud party and its allies nor the opposition bloc under Gadi Eisenkot secured the 61 seats needed for a parliamentary majority.
Likud accused the Arab parties of electoral fraud, saying the elections were "stolen by Arab parties that support terrorism and the destruction of the Jewish state".
Arab citizens make up about one-fifth of Israel's population.
Most are descendants of Palestinians who remained in the country following Israel's establishment in 1948.
Although they hold Israeli citizenship and have the right to vote, ultranationalist Jewish parties have traditionally refused to co-operate with Arab parties, some of which they regard as sympathetic to the Palestinian cause.
According to the news website Ynet, Shin Bet domestic intelligence chief David Zini requested a confidential meeting on Wednesday with the chairman of the Central Elections Committee, Judge Noam Sohlberg, to inform him of suspicions of foreign interference in the election.
Public broadcaster Kan cited an unnamed security source as saying that Qatar had allegedly financed groups working to mobilise voters in Israel's Arab community.
However, no evidence of foreign interference or wrongdoing by representatives of the Arab parties has been made public.
Qatar's foreign ministry rejected the allegations on X, saying the country should not be made a scapegoat for the political failures of certain Israeli politicians.
Israeli President Isaac Herzog called for a thorough investigation of all suspicions while warning against "bringing an entire community into disrepute that has sought to exercise its right to vote and actively participate in democracy".
Communications Minister Shlomo Karhi, a member of Netanyahu's Likud party, called on X for the opening session of the new parliament to be postponed until all allegations had been investigated.
"If it turns out that votes were bought with foreign money, this must have immediate consequences for the election results, up to and including their annulment," he said.
The official final results must be published by November 4, eight days after the election, while the new parliament is due to convene by November 10.
Eisenkot, leader of the opposition Yashar party, said the details and extent of the allegations remained unclear.
He accused Netanyahu of delaying the timely publication of the election results and seeking to create grounds to delegitimise the work of the parliament.
The Arab Balad party accused Netanyahu and his allies of laying the groundwork for rejecting the election results through unfounded allegations of foreign interference and vote-buying.
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