Russia's ambassador to Canberra has insisted the Kremlin had no motivation to kill a former spy in the UK and suggested Britain might be involved.
Grigory Logvinov believes a full investigation into the attempted assassination is needed before blame can be attributed.
"I'm afraid Russia would be the last country to have any motive," Mr Logvinov told the ABC on Friday.
"But the other countries, they have much stronger motives, including Great Britain."
Former double agent Sergei Skripal and his daughter are fighting for their lives in hospital after being poisoned by a military grade nerve agent in Salisbury, England.
Britain and its western allies are blaming Russia, but Mr Logvinov questioned what possible motive Moscow could have.
"This guy, he was arrested, he was sentenced, he served his term, he was pardoned and expelled from the country," Mr Loginov said.
"What's the use for Russia to assassinate him in this way, just on the eve of the presidential elections, and when the world soccer championship is approaching?"
CCTV image of Sergei Skripal buying groceries at the Bargain Stop convenience store in Salisbury on February 27, 2018. Source: Getty
Earlier, Foreign Minister Julia Bishop argued Russia had "no plausible excuse" for the attempted assassination.
Ms Bishop said Russia was either behind a nerve gas attack on a former spy in the UK, or the country had lost control of its chemical weapons supply.
The foreign minister believes there are global security ramifications for the assassination attempt on Mr Skripal and his daughter Yulia on March 4.
Australia has sent people to Moscow to follow up on the UK's accusations that Russia is behind the attack.
"There seems to be no plausible excuse - either the Russian State was behind it or Russia has lost control of its chemical weapons stockpile," Ms Bishop told the ABC.
"Either way Russia must answer these accusations."
Ms Bishop said Australia would work closely with the UK in the short-term, backing Britain's decision to expel 23 Russian diplomats and cut off high-level contacts with Moscow.
Australia will continue ongoing sanctions, including targeted financial sanctions introduced after threats to the Ukraine in 2014 and trade sanctions and travel bans introduced in 2015.
"We keep our sanctions against Russia under constant review and will continue to work very closely with the United Kingdom and other like-minded partners as the UK's investigation into this horrendous act continues," Ms Bishop said.
But Australia has no plans to introduce a Magnitsky Act, like those in the UK, United States and Canada, which allow sanctions against Russians connected to human rights violations.
Longer term, Ms Bishop believes Australia can play a role in a coordinated international campaign against chemical weapons.
