"Serious allegations" against Mr Wareing have been received by Labour's Chief Whip, Nick Brown, and he has referred what one MP called "a sad case" to the Parliamentary Commissioner for Standards, Sir Gordon Downey.
Two years ago Mr Wareing, who is chairman of the all-party British-Yugoslav parliamentary group, was criticised by his party for holding talks with the Bosnian Serb leaders Radovan Karadzic and General Ratko Mladic, whose forces had been responsible for a programme of ethnic cleansing.
Yesterday, the Parliamentary Labour Party adopted a new rule to allow suspensions in these cases as previously the party could only expel MPs who had transgressed the rules but could not take any action until the case had been proved.
The party appears to have learnt the lesson of the cash-for- questions affair during which the leadership of the Conservative Party was powerless to take action against MPs who appeared to have broken the rules but had not gone through the procedure. While Labour is deeply embarrassed at the opening of a second sleaze front after only seven weeks in office, the leadership wants to show that it is prepared to take firm action against misbehaving MPs in contrast to the Conservatives.
Next week, Labour's ruling National Executive is expected to decide to remove the right of the newly-elected MP for Glasgow Govan, Mohammad Sarwar to hold office in the party over allegations that he offered bribes to rival parliamentary candidates and Mr Brown is expected to follow this by suspending the whip.
Mr Wareing, the MP for Liverpool West Derby, will retain his full salary while the allegations are investigated.
In a statement issued last night, Mr Wareing did not deny the allegations - which are thought to have come as a result of a complaint within the Labour party - and said he "welcomed" the Chief Whip's decision.
He added: "I recognise why the Chief Whip felt it necessary to exercise his newly acquired powers of suspension until such time as Sir Gordon Downey has made his decision."
He also regretted "any embarrassment which my actions may cause my political colleagues, my constituency party and my constituents".
Mr Wareing, 66, a former lecturer, who holds Liverpool West Derby with a majority of almost 26,000, has been in Parliament since 1983 and was an opposition whip between 1987 and 1992. He has a longstanding interest in Eastern Europe and is vice-chairman of the Russian Group as well as holding the chairman's post with the British-Yugoslav group.
In the last register of member's interest, Mr Wareing's only entry is an overseas visit to Germany paid for by German Television.
A Labour Party spokesman said last night: "This suspension is a result of serious allegations relating to the Register of Members' Interests."Reuse content