Britain is "incredibly grateful" to Australia for backing the UK's move to boot out 23 Russian diplomats over a chemical attack on a former Russian double agent.
But the acting high commissioner to Australia would not reveal if the British government is pushing Malcolm Turnbull to also kick Russian agents out.
The prime minister declared solidarity with the UK as it completes its investigation into the "heinous" nerve agent attack carried out on English soil.
"We share the UK's outrage over this targeted attempt to commit murder using chemical weapons," Mr Turnbull said in a statement.
"There is no circumstance that justifies the use of such indiscriminate, abhorrent weapons."
The United Kingdom's acting high commissioner to Australia Ingrid Southworth said Russia challenged everyone who believed in international law.
"This is part of a pattern of Russian behaviour, from the assassination of Alexander Litvinenko, through to the shooting down of MH17, where sadly Australian lives were lost," Ms Southworth told reporters on Thursday.
"So we are incredibly grateful for the support of the Australian government at this time."
But Ms Southworth would not say if she had asked Australia to also kick diplomats out.
"As one of our closest national security partners, we will continue to work very closely with the Australian authorities in the days ahead," she said.
Australia conveyed its serious concerns overnight at a meeting of the Organisation for the Prohibition of Chemical Weapons in The Hague.
British Prime Minister Theresa May has publicly blamed the attack on Moscow.
Russia denies any involvement in the attack on ex-spy Sergei Skripal and his daughter Yulia, who have been critical in hospital since they were found unconscious on a bench in the city of Salisbury on March 4.
Foreign Minister Julie Bishop on Wednesday said Australia may consider upgrading sanctions against Russia after the UK concludes its inquiry.
Opposition foreign affairs spokeswoman Penny Wong said Labor supported the government in its stance on the attack.
