"That's eight votes against your party from me," the poster added.
The tweets prompted a user to alert the Electoral Commission who in turn contacted police.
"Our investigation of this matter has resulted in a referral to police," said a commission spokesperson.
A police spokesperson confirmed a complaint had been laid by the Electoral Commission regarding a series of posts on social media.
They would be investigating the matter.
There has been one other instance in the past week of alleged dual voting.
The commission said a person had been referred to police after they claimed to have voted multiple times.
In the 2017 election 37 people were referred to police who appeared to have voted more than once.
Police prosecuted one person.
The commission spokesperson said in most cases dual voting was unintentional.