An estimated 24.10 per cent voters exercised their franchise in the by-elections to Malwan assembly constituency in Konkan till noon on Saturday.
Maharashtra Revenue Minister and Congress candidate Narayan Rane is facing Parshuram Uparkar of Shiv Sena.
Rane is seeking fresh mandate from the assembly constituency after he quit the seat following his switch to the Congress in July.
Sindhudurg Collector Vijya Laxmi Bidari said Uparkar has lodged a complaint regarding his polling agents not being allowed to function at Harkud Budruk village.
Observers are taking note of the same, she added.
There have been other complaints regarding stray incidents of verbal skirmishes at some places, but they were minor in nature, Bidari said.
Even after 1700 IST, when polling will end, the deployed police force will be asked to stay on guard, the collector added.
Meanwhile, Rane cast his vote with wife and two sons at his native Varvade village. His mother Laxmi also cast her vote.
Later talking to reporters, Rane denied that Shiv Sena polling agents were being threatened. "They have no workers left here. All of them have joined the Congress," he said.