Dead KGB spy Alexander Litvinenko accused Vladimir Putin of being paedophile - wife

Alexander Litvinenko.

The widow of poisoned spy Alexander Litvinenko has told the public inquiry into his death that her husband accused Russian president Vladimir Putin of being a paedophile.

Marina Litvinenko said ex-KGB agent Mr Litvinenko wrote an article shortly before his death in 2006 which questioned why Mr Putin kissed a young boy's stomach under his t-shirt during a tour of the Kremlin.

The inquiry at the Royal Courts of Justice in central London was shown a copy of the article which featured a photograph of Mr Putin and the boy and the headline "Kremlin Paedophile".

Giving evidence today, Mrs Litvinenko, 52, said: "It was written in 2006 after everybody saw how Putin behaved when he met a little boy in a Kremlin tour group. He went under his t-shirt and kissed his stomach."

Robin Tam QC, counsel to the inquiry, said: "You have no idea if that allegation is true?"

Mrs Litvinenko replied: "No, I have no idea."

She told the inquiry her husband was paid £2000 (NZ$4171) a month for "consulting" British intelligence services after claiming political asylum in the UK.

Mr Litvinenko, 43, died at University College Hospital nearly three weeks after drinking tea laced with radioactive polonium-210 while meeting two Russian men - one a former KGB officer - at the Millennium Hotel in London's Grosvenor Square.

His family believes he was working for MI6 at the time and was killed in November 2006 on the orders of the Kremlin.

Former KGB bodyguard Andrei Lugovoi and Dmitri Kovtun have been identified as the prime suspects in the killing, but both deny any involvement and remain in Russia.

- AAP