Security at the Indian Ocean Rim Conference has been reviewed after explosives were found hidden in an Australind estuary.
A second suspicious package, believed to be explosives, was detonated in water near a jetty about 5pm today, more than 24 hours after police divers found it near where about 3kg of TATP, the same explosives used in the 2005 London bombings, was found earlier in the week.
The explosives were found at the same time foreign minsters were gathering in Perth for the economic summit.
Risk assessments and security measures around the foreign dignitaries have been reviewed.
Security at all critical infrastructure has been assessed in the wake of the finds.
Divers are continuing to scour the Leschenault Estuary for more packages.
Today police also admitted that a south-west officer who initially handled the first packages of explosives found in the estuary needed medical treatment after being burned by the powdery substance.
Police Commissioner Karl O'Callaghan said: "My understanding is he received a minor chemical burn to one of his fingers.
He said a presumptive test done by the officers gave them an indication that the substance might be an illicit drug and so the officers involved had treated it like any other drug.
"Drugs get cut with all sorts of different chemical compounds so it's not completely unheard of that you could get an injury from something that's mixed up with a drug," he said.
But he said procedures would be reviewed in light of the later realisation that the compound was homemade explosives.
During a joint press conference with Premier Colin Barnett this morning, Mr O'Callaghan said authorities had still not identified what was in the package found submerged yesterday in a similar area to where the first explosives were found.
He said police were taking advice from the Australian Defence Force about how best to deal with that package.
"It is being treated obviously as a volatile potentially explosive package but as I said before we don't know what's in that," he said.
Mr Barnett said there was no immediate danger to the public but precautionary measures were being taken.
"All that is being done is what needs to be done," he said.
Opposition leader Mark McGowan said he called on Mr Barnett to hold a proper press conference or make a statement to Parliament regarding any issues of public safety and on going security in regards to a very serious issue.
"I note today Mr Barnett has followed my advice" he said.
Chemical manufacturer Cristal relocated its 50th anniversary celebrations planned today at its Australind plant to a nearby golf course in light of the police operation. But the company said it still expected to have an open day at the plant on Sunday.
Mr Barnett and Mr O'Callaghan again appealed for anyone with information about the explosives to call Crime Stoppers on 1800 333 000.