Tony Abbott fears over-protective ministers could be getting in the way of plans to set up a homeland security-style counter-terrorism office in Australia.
The idea has been floating around for years, with some suggesting Immigration Minister Peter Dutton wants to lead the super-agency.
The former prime minister said he could see an argument for a Home Office-type situation in Australia, now and when he was in power.
"What we don't want is to see turf-protecting ministers getting in the way of the best possible counter-terrorism arrangements," Mr Abbott told Sydney's 2GB radio on Wednesday.
"That's what I fear that, in the end, we might end up with sub-optimal arrangements because some ministers start protecting their turf."
Asked why Malcolm Turnbull hadn't gone ahead with it, Mr Abbott replied: "That's a good question."
The leader-cum-backbencher echoed British Prime Minister Theresa May's comment that "enough is enough" when it comes to fighting extremists.
They have effectively declared war and have to be treated as enemies - not simply misguided individuals who deserve compassion.
"These are our enemy and they need to be dealt with much more severely," he said.
He said it was critical that vetting of immigrants be up-scaled from when Labor was in power, adding that it was right and proper for authorities to look long and hard at people who want to come into the country.
"The last thing we want is people coming into our country who don't like us and might in some cases want to do us harm."
