He did so to point to the hypocrisy of the critics of Netanyahu's call this month on election day.
Here is the original Hebrew of Netanyahu's call which rankled US President Obama:
"The rule of the Right is in danger. Arab voters are moving in large numbers to the voting booths. Left-wing NGOs are transporting them in buses. We don't have a V15, we have an Emergency Call-up #8, we have only you. Get out to vote, bring friends and family. Vote Likud to close the gap between us and Labour."
Going back to Peres, here are the two most relevant sections:
Peres calls up heads of Arab councils in a special personal effort and tells them "every vote is important, every vote in critical, it's a close contest".
Peres gets himself interviewed by Kol Yisrael's Arab affairs reporter who informs the country that Peres said, "Get out and vote, every vote is important." And he yells at the Justice Minister David Libai, "we're losing the elections, get out to Baqa Al-Garabiya, get the people out into the streets."
In addition to what I wrote, here and here, I emphasize that the voting in Israel is via proportional representation which can favor an organized voting pattern as there are no constituencies. The country is itslef one voting district.
But whatever you think of Netanyahu, think the same of Peres.
Check out what Bibi said later that day and what did Arab MKs say, too.