Authorities are urging Victorian householders to take extra care when switching off their lights for Earth Hour this weekend.

Melbourne's Metropolitan Fire Brigade (MFB) said people needed to be prepared for the safe use of candles and open flames when the lights go down on Saturday evening.

Earth Hour is a global initiative aimed at getting residents and businesses to switch off non-essential lights for one hour in a symbolic bid to combat climate change.

Melbourne is one of 20 cities around the world to take part in the initiative.

The MFB is urging families to exercise care with open flames between 8pm and 9pm (AEDT) on Saturday.

"Candles, oil burners, matches and lighters can all be extremely dangerous if not used safely," MFB community safety commander Frank Stockton said.

Among the safety tips from MFB are:

- Candles and oil burners should only be lit well away from curtains and open windows;

- All open flames should be extinguished before leaving home or going to bed;

- Children should never be allowed to have access to matches or lighters;

- Adults should be present at all times when a candle or an oil burner is being used;

- Household smoke alarms should be tested to ensure they are in working order.