Peter Mandelson will push for increased British trade in Moscow as his links with a Russian billionaire continued to cause controversy back in the UK.
The peer has denied doing any "favours" for Oleg Deripaska as Labour and the Tories continued a tit-for-tat war over the so-called "yachtgate" affair.
The Business Secretary, leading a trade delegation in the Russian capital, was accused by the Tories of appearing to have "something to hide" by not publishing a full account of his dealings with the aluminium magnate.
But he was backed by Prime Minister Gordon Brown who renewed his calls for an inquiry into what he said were claims of "clearly unlawful" behaviour from Conservatives.
Summer visits to the oligarch's luxury yacht by the then EU trade commissioner and shadow chancellor George Osborne have sparked questions about both the senior politicians' activities.
Mr Osborne strongly denies claims, made by the financier friend who arranged the meeting, that he tried to secure a party donation from Mr Deripaska, who as a foreign national is barred from funding parties.
And Lord Mandelson, brought back into the Cabinet in a shock reshuffle move this month, points to statements by EU officials that he did not interfere in a decision to cut tariffs which benefited Mr Deripaska.
"A lot has been said about the relationship I have with one particular Russian businessman," he told Sky News.
"All I would say about that is that he has never asked for any favours, I have never given him any favours and that is what the European Commission in their examination of the issue has very firmly put on record."
But shadow foreign secretary William Hague said Lord Mandelson, who has admitted knowing the Russian for twice as long as previously publicly stated, said the "whole country" wanted more information.
