The Black Saturday bushfire class action against electricity company SP AusNet is expected to conclude in Melbourne on Wednesday after 16 months.

The case, brought on behalf of more than 10,000 Kilmore East and Kinglake residents, is the longest-running action of its kind in Victoria.

SP AusNet owned and operated the power line that sparked the fire, which killed 119 people in 2009.

Victims’ representatives told the Supreme Court of Victoria the company should have replaced the damaged power line, which was 34 years old.

But SP AusNet says it did not know there was a risk, and it does not owe a duty of care to bushfire victims under Victorian law.

A $4 million courtroom was built for the unprecedented case, and the hearing was web-streamed to plaintiffs, allowing them to watch proceedings from home.

A judgement is not expected until next February.