The investment, spanning a decade, includes $60.6 million for aerial drones and other autonomous vehicles.
They'll be used to map inaccessible and fragile areas of East Antarctica, establishing an "eye" using integrated sensors and cameras that feed real-time information.
Australia lays claim to more than 42 per cent of the continent - known as the Australian Antarctic Territory - where it has three bases: Mawson, Casey and Davis.
"We are a treaty nation when it comes to Antarctica and we take those responsibilities incredibly seriously," Prime Minister Scott Morrison said in Tasmania on Tuesday.
"Not everybody respects those obligations and those stewardship responsibilities. This gives us eyes on Antarctica."
Mr Morrison indicated he had concerns about China's expansion in Antarctica, adding there were some who sought to "exploit its resources".
"It is very important that we are very clear in our understanding about what activities are being undertaken ... and that there is an accountability and transparency," he said.
Some $35 million will be spent on four new helicopters with a range of 550 kilometres.
Environment Minister Sussan Ley said the new drones and helicopters will allow researchers to go inland into areas they haven't been before and set up mobile base stations.
She said the investment also strengthened the Antarctic Treaty System, amid concerns regarding Chinese and Russian assertiveness in the region.
"It is strengthening our presence, it is strengthening our science, it is strengthening our environmental protection," she told the ABC.
"There have been pressures from within the Antarctic Treaty System. There are times over the history of our involvement in Antarctica when you need to step up and this is one of those times.
"It is new investment that locks in a 20-year strategy in Antarctica and that is important."
Mr Morrison said the investment would create 685 jobs, including in Tasmania which acts as Australia's gateway to Antarctica.
Greens senator Peter Whish-Wilson questioned whether the announcement was new, given the federal government earmarked a $413 million investment in 2016.
Australia last year abandoned plans to build the first concrete runway on Antarctica on economic and environmental grounds.
"We also know the government's doomed runway project spared $300 million of expenditure into the region - making part of (the) funding announcement a reappropriation of funds from a broken election promise," the Tasmanian senator said.
Some $136 million will go towards inland traverse capability, critical charting, mobile stations and environmental protection.
About $17 million will be spent on Southern Ocean marine science and a state-of-the-art krill aquarium in Hobart.
Bob Brown Foundation campaigner Alistair Allan said the funds could be better used on protecting Antarctica from the threat of climate change.
"The prime minister should use this $800 million to help transition out of fossil fuels right now," he said.
"Not fly a bunch of cameras over Antarctica to show us what we are about to lose."
