"We are closely monitoring the carbon dioxide through one of the world's most comprehensive geosequestration monitoring programs and every indication is that the carbon dioxide is behaving just as researchers have predicted," chief executive Peter Cook said.

"The injection process is proceeding very well and we are now starting on our next 10,000 tonnes."

The CO2CRC Otway Project, near Victoria aims to demonstrate the safety and security of the transport, injection and storage of carbon dioxide, the world's most common greenhouse gas, in the deep subsurface.

The geosequestration package is designed to process CO2-rich gas from the Buttress Wellhead and compress the gas before re-injection into the depleted Naylor reservoir, about 2km away.