The poor treatment of veterans following the Vietnam and Korean wars has been brought to the fore on Anzac Day.
Opposition Leader Peter Dutton said the service of Australians in both conflicts should always be remembered.
This year marks 50 years since the end of Australian involvement in the Vietnam conflict and 70 years since the Korean War came to an end.
"To this day, the Korean War can appear as a mere blip on the historical radar, receiving less attention than it should," Mr Dutton said.
"Narratives of shame and controversy continue to colour the Vietnam War."
Mr Dutton said while protests and anti-war sentiment clouded opinions towards Vietnam veterans, their service was not in vain.
"Our veterans deserve much better, our long dead deserve much better," he said.
"In the case of Korea and Vietnam, let us never forget this: Australians fought in foreign lands to defend those who desired self-determination and liberty."
As people paused nationwide to remember on Anzac Day, Veterans' Affairs Minister Matt Keogh said more needed to be done to ensure defence personnel were looked after following their service.
"We have a responsibility to look after our veterans, whether they've served overseas, whether they've come with injury or mental illness from that or served in Australia," he said.
"We're doing everything we can to look after them, but there's absolutely more to do and I acknowledge that."
Mr Keogh, who represented Australia at the Gallipoli dawn service, said attendance was expected to be the largest since centenary commemorations in 2015.
"There's an element of people who were very interested to be able come over the last few years and haven't been able to attend," he said.
"What we really see is that people have seen the service that's been rendered by our defence force personnel not just way back in World War I, but all the way through to recent conflicts."
Mr Keogh said the large numbers of people attending dawn services and commemorations across Australia and overseas reflected the recognition of service by broad sections of the community.
"What we've really seen Anzac Day become is not just about one conflict, it's now a day where we commemorate not just those that died but all those people that have served in our uniform on our behalf in conflict," he said.
Defence Minister Richard Marles said Anzac Day was also a time to reflect on the 1200 Australians on military deployment.
On a recent trip to England, Mr Marles met with Australian defence personnel training Ukrainian troops to defend their country from Russia's invasion.
"To see people putting on the uniform of their nation, knowing full well that this might be a moment of personal and ultimate sacrifice is an extremely poignant and very inspiring thing to see," he said.
"The Australians who are training them are doing incredible work. Today is a moment where we remember them and all of those who have served, particularly those who paid the ultimate sacrifice."
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