As reported, showboating MP Kaimiņš pretended to be someone else when a Sputnik reporter tried to reach Regional Alliance head Mārtiņš Bondars but dialed Kaimiņš' number by mistake.
Bondars told LTV that as the call and the news appeared before the municipal elections had ended, it amounts to influencing the election.
"Mr Kaimiņš should answer for his actions in front of a court," he said.
However Bondars said he won't be the one to turn to the court, saying there's no point "wasting time" pressing charges, "if the authorities aren't clear about the fact that this is a very serious electoral violation".
Kaimiņš made his name first as an actor, then as a shock-jock type host of internet talk show Sunu Buda (Dog House) before joining politics.
His erratic behavior, which includes walking through the corridors of power with a webcam and being arrested after causing trouble in a Riga restaurant, saw him part company with Latvia's Regional Alliance, the party he was elected to serve.
After a falling-out with Bondars, he founded KPV LV.
Previously the Kremlin-controlled Sputnik info agency posted an audio recording of an interview between Kaimiņš and one of its workers, in which Kaimiņš appears to pose as Bondars, offering various views on the municipal election campaign in Riga, where Bondars was a candidate for the mayor's seat (and eventually finished in second place).
In a highly provocative move Kaimiņš confirmed that he was Bondars and said a pact had been agreed between LRA and Riga mayor Nils Usakovs - an unfounded and politically sensitive claim.
The error did at least lead to Sputnik setting a remarkable precedent by apologizing to its readers for misleading them - and to Bondars.