Two people have been arrested after a volunteer for Australia’s right-wing populist party One Nation was allegedly assaulted with a baseball bat.

A man, 37, and a boy, 14, were arrested on Sunday night after an incident outside the volunteer’s home in Torquay, about 100km (62 miles) south-west of Melbourne.

The man was charged with assault offences and remanded in custody while the boy was issued with a caution. The volunteer was hospitalised with non-life threatening injuries, police said.

One Nation’s Victorian leader Warren Pickering claimed the attack happened after the pair “interfered with” election signs on the volunteer’s property.

Pickering said the alleged assault was “un-Australian and unacceptable”.

“Political violence or intimidation of any kind against anyone is unacceptable in this country,” he said.

“If you don’t like someone’s politics, you vote accordingly. You don’t assault them.”

Victorian Premier Ben Carroll described the attack as “shocking”.

“Whether you’re wearing a red, a blue, an orange, or a green T-shirt, they are volunteers,” he said.

“They are out there doing what they believe is right, and no one should be coming under attack.”

The alleged attack comes during a state election campaign in Victoria, and amid a reckoning in the country more broadly over the tone of political debate, after the attack on Federal MP Helen Haines last month.

Police have not detailed a motive for the incident – which left Haines needing both of her legs amputated – but politicians, law enforcement, and experts have said heated public discourse is heightening the threat of political violence in the country.