Head of the committee Jamal al-Shawbaki said a committee would be set up to investigate violations.
Hamas said in a statement, a copy of which was received by Aljazeera, that its candidates' lists had won the majority of votes in the elections.
Hamas lists won a majority in 31 municipal centres in addition to winning a number of seats, along with other lists in other centres, the statement said.
Both Fatah and Hamas disputed the preliminary count.
Pending an official tally, President Mahmoud Abbas' ruling Fatah party seems to have come out ahead in a second round of Palestinian municipal elections, but Hamas won important urban centres in a show of strength.
Election officials said on Monday Fatah captured about 50 of 84 municipal councils in the West Bank and Gaza Strip, but Hamas won around 30, including the Gaza border city of Rafah and the West Bank town of Qalqilya.