Abe's Liberal Democratic Party, in partnership with the junior New Komeito, was expected to claim a comfortable majority in the 127-seat Tokyo Metropolitan Assembly, according to exit polls by a variety of local media.
The ballot was widely being seen as an indicator of public opinion in the run up to upper house polls expected on July 21.
"The LDP, combined with New Komeito... Was on course to secure the majority of the assembly," national broadcaster NHK said shortly after polls closed at 8 pm (1100 GMT).
Official results are expected to be available today or early yesterday.
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It was the first voters' verdict on Abe's administration, which came to power in December and still enjoys approval ratings of more than 60 percent.
An economic policy blitz dubbed "Abenomics", which blends massive monetary easing, big fiscal spending and a series of reforms aimed at freeing up businesses, has dominated the opening months of the Abe government.
Japan's sleep-walking economy -- the world's third largest -- has been given a jolt by the moves, with the yen shedding some of its export-sapping strength and the stock market putting in the best performance in the developed world this year.
If Abe can secure control of the upper house in the July polls, it will relieve a legislative bottleneck and give him free rein to push through the painful reforms commentators say Japan desperately needs.
Detractors warn that with a majority in both houses, Abe will take his eye off the economic ball and push the conservative social agenda he was known for before the election, including a possible reassessment of Japan's wartime history.