Scott Morrison has moved to clarify when his government became aware of a proposed security pact between China and the Solomon Islands.
Mr Morrison on Wednesday told reporters "this is no surprise to us" when questioned on the pact despite Foreign Minister Marise Payne and Pacific Minister Zed Seselja saying they only became aware of it through leaks on social media.
On Thursday, the prime minister said: "We have always been aware of the risks of an agreement like this."
"I have known for some time the risk of a deal such as this coming about. This is why the first place I went to after the last election (in 2019) was the Solomon Islands," he said.
"We've been aware of the Chinese seeking to obtain an agreement like this, as they have been in Papua New Guinea and other countries in the Pacific, as they have done in African countries."
Labor has criticised the government for not acting sooner, with campaign spokesman Jason Clare saying the development was an "epic fail" on Mr Morrison's watch.
"The prime minister said, 'This is not a surprise'. If it's not a surprise, it makes it worse. It means he knew this was happening and he didn't act fast enough," he said.
Retired Admiral Chris Barrie says the Solomon Islands turning to China after 15 years of Australian assistance constituted "a failure of Australian government policy".
"We have to step up and be a good friend to countries in the Pacific like the Solomon Islands," he told a clean energy forum in Sydney.
"That means a change in climate policy because they look at what we're doing to climate change and say where are you when we're facing the loss of our country."
Defence Minister Peter Dutton lashed any suggestions climate policy was the issue.
"The problem is China and President Xi, let's be very honest about it. It's not about climate change," he told Sky News.
"China is on a very different path and I'm not going to sugarcoat what the future years and couple of decades look like in our region."
He also defended sending the Pacific minister, saying the response was discussed in depth during cabinet national security committee meetings.
"We have taken the advice of the chief of the defence force and the Department of Foreign Affairs and Trade," he told the Seven Network.
"We've had those briefings and we've gone through what was known and what was available to us in what has been a delicate period and it was a very deliberate decision to send Zed over Marise Payne."
But Mr Dutton appeared to contradict the prime minister over the threat China poses in the Solomon Islands.
Mr Morrison said Honiara had categorically ruled out a military base being established under the pact between the Solomons and China.
But Mr Dutton chastised China for "not playing by the same rules".
"You can expect the Chinese to do all they can now that they've got this agreement signed," Mr Dutton told Sky News when questioned on whether troops would move in.
"(China said) the South China Sea would not be militarised (and) today, they're militarised. They've got airstrips. They've got fuel depots. And that's the reality of China under President Xi."
Mr Morrison later backed his defence minister, telling reporters China was an autocratic nation that was not playing by the normal rules in how it sought to influence other nations in the region.
"I can't go into all the details as to how Australia is able to know the specific information, as they are security matters," he said.
"But what I do know is we have always been very conscious of the threat of China being able to influence a nation in our region."
