Labor's deputy leader Richard Marles accused the government of chest-thumping on the Solomon Islands security deal with China but doing little to improve Australia's relations with Pacific nations.
Following a dawn service to commemorate Anzac Day, Defence Minister Peter Dutton said the only way to preserve peace was to "prepare for war".
"That's the reality. We are a country with a proud heritage that we commemorate today, the most important day on our calendar," he told the Nine Network.
"We're determined to make sure we can have peace in our country."
Yet Mr Marles said Australia was facing strategic circumstances more complex than since World War II and the Liberal-National coalition had failed to prepare.
"This is a government which beats its chest but when it comes to actually delivering and doing what needs to be done, this is a government which repeatedly fails," he told reporters in Darwin on Monday.
"We've seen six defence ministers in nine years ... words are one thing, action is what matters and this is a government which repeatedly fails, as it has in its management of relationships in the Pacific."
Navy chief Vice Admiral Michael Noonan said the budget announcement to recruit an extra 18,500 personnel was a sign that security is extremely important.
"It is troubling there is a very different dynamic in our region at the moment and certainly the commitment of the government is testament to the fact it is a challenging time," he said.
Meanwhile, a Liberal backbencher said the Solomon Islands security deal with China was a "money grab" from the Pacific nation.
Queensland MP Phillip Thompson, who served in Afghanistan as a member of the Australian Defence Force, identified China as the greatest threat to Australia's national security.
While Australia and China should not engage in a bidding war with the Solomon Islands it was important to recognise China's financial influence in the region, the backbencher said.
"What we've seen with (China's) security pact in the Solomon Islands, it's a money grab from the Solomon Islands," Mr Thompson told Sky News on Monday.
"(Australia has) always been there in support and helping the Pacific family. China comes in with a big bag of cash."
Both the Liberal and Labor camps have suggested China could have engaged in bribery to secure the deal.
Labor's defence spokesman Brendan O'Connor said it was clear China did not follow the same rules as other countries.
"It may well be the case that they've acted in an improper manner in terms of convincing the Solomon Islands to enter into such an arrangement," he told ABC Radio National.
But he added the coalition had failed to maintain a good relationship with the Solomon Islands.
"(Australia) should have been doing more," he said.
"The current foreign minister should have visited the Solomon Islands, we believe there should have been more engagement and we should not have cut foreign aid to the region the way we have over the last almost decade."
Mr Dutton said he wanted Australia to have a better relationship with China, but reiterated his assertion it was the Chinese government which had changed the narrative.
"The Chinese operate by very different rules and they do it here, they do it in Africa, they do it in other parts of the world," he said.
"We want a normalised relationship with China as quickly as possible, but these acts of aggression we're seeing at the moment aren't acceptable to our country or to countries that stand for what we stand for."