Prime Minister Tony Abbott says the protesters who disrupted his Adelaide University speech were disrespectful but had a right to be heard.
Protesters tore down a security fence outside the lecture theatre where Mr Abbott was delivering a speech on Thursday night.
Dozens of police, including 10 mounted police, pushed the protesters back with some of them being knocked over.
The prime minister said on Friday that people had a right to protest against the government’s policies but they should keep it peaceful.
“People are perfectly entitled to protest,” he told reporters.
“If they want to tell me they disagree with the government’s policies on a whole range of issues, I hear what they’re saying.
“I respectfully disagree with them, they rather disrespectfully disagree with me. That’s life in our democracy.”
The prime minister inspected early construction works on the $1.5 billion North-South Corridor upgrade in Adelaide’s west, a project jointly funded by the state and commonwealth governments.
South Australia’s Labor premier Jay Weatherill has campaigned heavily against the federal budget, saying it will force unsustainable cuts to health and education funding.
But Mr Abbott said it was up to the states to allocate funding to individual schools and hospitals.
“I accept the premier’s point and it’s not just Premier Weatherill, it’s the coalition premiers as well,” he said.
“(They) would have preferred this government to continue with the arrangements that were made under the former Labor government.
“I understand that the states would always like more from the Commonwealth but our responsibility is to keep our spending sustainable.”
The prime minister would not be drawn on whether the government had abandoned a pre-election promise to build a new fleet of submarines in Adelaide.
The project is considered critical for the state’s manufacturing sector, with thousands of jobs at risk from the looming closure of Holden.
“Whatever decision the government ultimately makes on the design and build of the next generation of submarines, there is going to be a massive amount of work on the future submarine project, one way or another, here in Adelaide,” Mr Abbott said.