Russia's ambassador to Australia has been hauled in by Foreign Minister Julie Bishop to explain his country's role in a nerve gas attack in the UK, hours after an extraordinary press conference in which he tried to cast doubt over whether the incident even happened.

Key points: Grigory Logvinov questioned whether there was evidence Skripals had been poisoned

Grigory Logvinov questioned whether there was evidence Skripals had been poisoned He repeated denials two Russian diplomats being expelled from Australia were spies

He repeated denials two Russian diplomats being expelled from Australia were spies Foreign Minister Julie Bishop met with ambassador this afternoon

Ms Bishop announced yesterday that two Russian spies would be expelled from Australia in response to the attack on Sergei Skripal and his daughter Yulia, who were found unconscious on a park bench in the city of Salisbury earlier this month.

The UK Government said they were attacked with the nerve agent Novichok, a chemical weapon developed by the Soviet Union in the 1980s.

Prime Minister Malcolm Turnbull called the poisoning a disgraceful attack on the sovereignty of the UK and the rule of law.

But during a press conference with Australian journalists this morning that lasted more than an hour, Russian ambassador Grigory Logvinov questioned what happened to Mr Skripal.

"My gosh, who has seen the Skripals after their alleged poisoning?" he asked reporters.

"Who has seen any real medical report beside the political statements that they were poisoned with some alleged nerve agent?"

A British judge, citing an unidentified doctor who is treating the pair, said on Friday the Skripals were in a stable but critical condition in a local hospital and had likely suffered lasting brain damage.

Ms Bishop met the Russian ambassador at Parliament House this afternoon to outline Australia's position, and allowed cameras to film the start of the meeting.

"Mr Ambassador, I hope we can have a discussion today and you can provide these answers that the Australian people want from you: a credible explanation as to how this nerve agent was deployed in this attempted assassination," she said.

"We did not take this step lightly, but we share the deep concerns, indeed the outrage, that a chemical nerve agent could be deployed in this circumstance."

Ambassador also denied Russian wrongdoing in Crimea, MH17

During this morning's lengthy press conference, Mr Logvinov was pressed on whether he thought the attack on the Skripals was completely made up.

"If we start analysing anything, well we can come to such conclusion," he said.

"At least it is very primitively fabricated."

Sorry, this video has expired Russian Ambassador to Australia questions 'alleged' Skripal poisoning

The ambassador's comments led to several questions from journalists about whether he saw the accusations as part of a conspiracy against Russia.

"This is a well-orchestrated campaign … It is now up to the West to finally stop and understand that the anti-Russian campaign has no future," he said.

Journalists used the Russian briefing to press the ambassador to justify his claims, including that there were no spies operating out of the Russian embassy in Canberra.

"Do you realise how stupid you sound when you say there are no Russian spies in Australia?" he was asked.

"Well I don't feel stupid, because I know what I am saying," Mr Logvinov said.

During the lengthy briefing, Mr Logvinov also denied any wrongdoing by Russia in relation to the annexation of Crimea and the downing of Malaysia Airlines jet MH17 over eastern Ukraine.

Asked whether the world was on the brink of another Cold War, Mr Logvinov said: "If the West wants it."

Bishop unsurprised to hear 'Russian propaganda'

Before meeting with the Russian ambassador this afternoon, Ms Bishop said she was not surprised to hear his most recent comments.

"We have seen this script before. This is standard Russian propaganda," she said.

"We see it in relation to MH17, we've seen it over many years. This is nothing new. I expect nothing less from the Russian ambassador."

Sorry, this video has expired Julie Bishop says Russia's actions will not be tolerated

The two Russian diplomats who are being expelled, now identified as intelligence officers, have less than a week to leave Australia.

Mr Logvinov today repeated his earlier denial that the diplomats were spies.

He declined to identify the two officials who have been asked to leave the country, but said they were "absolutely legal career diplomats".

Paul Dibb worked in defence intelligence for nearly two decades and helped ASIO gather counterintelligence on the Soviet Union's capabilities in Australia.

Mr Dibb told The World Today that such denials were "standard operating procedure" for diplomats of any country.

"I watched him last night on 7.30 and [host Leigh Sales] asked him, 'Are these people spies?' and there was a sort of twinkling smile on his face and he said, 'Of course not'," Mr Dibb said.

"That's his job to say that.

"But listening to what Julie Bishop is saying, the careful words, there is no doubt in my mind [the advice from ASIO would have been] that these two people in the Russian embassy … are undoubtedly up to no good."