The Australian Electoral Commission has found a Liberal Party volunteer who helped residents of a Melbourne nursing home to vote at a mobile polling booth did nothing wrong.

Ian Smith, whose 96-year-old mother has dementia, said he was shocked yesterday to see a Liberal Party volunteer enter the temporary booth to assist at least a dozen residents to fill out their Senate ballot papers.

The Victorian manager of the Australian Electoral Commission, Steve Kennedy, said while party campaign workers were not allowed within six metres of a polling booth, this did not apply to mobile booths, such as at nursing homes, and the rules allowed party volunteers to assist voters in such circumstances.

Mr Kennedy initially told ABC Radio Melbourne he believed the incident should not have transpired and committed to investigate.

He later said the investigation had concluded no wrongdoing had occurred, and no further action would be taken.

"There has been no breach of the Commonwealth Electoral Act," he said.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 2 minutes 37 seconds 2 m 37 s State political reporter Richard Willingham on why Victoria will matter this election

The aged care home, in Kew in Melbourne's inner-east, sits within federal Treasurer Josh Frydenberg's electorate of Kooyong.

Mr Frydenberg is fighting to hold onto his seat against two high-profile challengers in Greens candidate Julian Burnside and independent Oliver Yates.

Mr Smith said he had been a member of the Labor Party in the 1970s but was no longer a member of any political party.