The Australian Energy Regulator (AER) on Tuesday slapped Energex and TasNetworks with fines after they breached the National Energy Retail Rules, and potentially put lives at risk.

TasNetworks was fined $60,000 and Energex $40,000, after they both failed to give a minimum of four days notice to people registered as having life support equipment in their homes.

This is not the first time incidents such as these have occurred. Ausgrid alone has received more than $100,000 in fines for six breaches of its life support protection obligations over the last 12 months.

Endeavour Energy, Ergon Energy, and ActewAGL have also been fined within the last year for the same offence.

Residential and small business energy users' representative group Energy Consumers Australia welcomed the announcement and backed the penalty.

"The AER's action today sends a strong signal to the sector about the need to ensure they have systems in place to support customers who rely on life support equipment," an ECA spokesman said.

Energex cut power twice to Queensland customers, while TasNetworks cut power to three Tasmanian customers requiring life support; each company received a $20,000 fine per infringement.

The first incident saw TasNetworks cut the power to a customer on life support on December, 2016 for around 45 minutes. The second incident occurred in February this year with the cut lasting nearly five hours. The most recent incident happened in April, with power lost for approximately 31 minutes.

"These events are regrettable and TasNetworks is working on ensuing these types of incidents are minimised," a TasNetworks spokesman said.

"In all cases four days' notice is required for a planned outage and, with respect to the three breaches, TasNetworks failed to provide the required notice period.

Energex's incidents occurred in September and October last year but outage times were not provided for either event.

An AER spokesman confirmed that no one died as a result of the power outages.

The AER stated that the life support customers had no effective prior warning of the planned interruption to their electricity.

"Protecting customers requiring life support equipment is an ongoing priority for the AER," AER chairman Paula Conboy said.

"It is imperative that these customers receive advanced notice of any planned interruption to their energy supply, so they can make alternative plans. This reduces any risk of harm occurring or more serious consequences for those customers."

It is understood that if the companies failed to pay the fines then the AER could bring court proceedings for the imposition of a penalty along with other orders to address any breaches.