FIFA's chief ethics investigator has said he will complete his probe into the bidding for the 2018 and 2022 World Cups by next week despite fresh allegations surfacing about Qatar's victory.

US attorney Michael Garcia, who met Qatar 2022 World Cup bid chiefs in Oman on Monday, said the investigation would conclude by June 9 and he would submit a report in mid-July.

It comes after the Sunday Times reported that it has gained access to millions of emails and documents which it claims show former FIFA executive committee member Mohamed Bin Hammam made payments to officials as part of a campaign to win support for Qatar's 2022 World Cup bid.

Qatar 2022 has distanced its bid from Bin Hammam, insisted there was no wrong-doing and said it would co-operate with Garcia's investigation. It is likely Garcia has had access for some time to the material which the Sunday Times has published.

Garcia said in a statement: "After months of interviewing witnesses and gathering materials, we intend to complete that phase of our investigation by June 9, 2014, and to submit a report to the adjudicatory chamber approximately six weeks thereafter.

"The report will consider all evidence potentially related to the bidding process, including evidence collected from prior investigations."

Meanwhile, Prime Minister David Cameron, who took part in the final throes of England's failed 2018 bid, said Garcia's inquiry should be allowed to take its course.

Cameron, speaking in Newark, said: "We will see what happens with this inquiry into the World Cup. And who knows what the chances may be for the future.

"There is an inquiry under way, quite rightly, into what happened in terms of the World Cup bid for 2022. We should let that inquiry take place rather than prejudge it. My memories of that bidding process are not happy memories in terms of the way the whole thing was arranged and the role of FIFA."

Cameron said he, David Beckham and the Duke of Cambridge were assured by numerous FIFA members of their support - in the end England secured only one vote apart from their own FIFA vice-president Geoff Thompson.

He added: "I'll always remember Beckham saying to me afterwards, he said 'I can cope with being lied to but I can't cope with people lying to the Prime Minister and the future king."

Garcia will also be reporting on the 2018 bidding process which was won by Russia.

In 2010, Nigeria's then FIFA member Amos Adamu told an undercover Sunday Times reporter that the Russians had offered him "co-operation" with building facilities and training players in Nigeria.

At the time, the head of the Russian bid, Alexei Sorokin, confirmed that Adamu had visited Moscow but said the visit was conducted "in conformity with FIFA rules" and had not involved the offer of any voting incentives.

Sorokin said in 2010 that "all bidders are likely to have made proposals to the various stakeholders" including "friendly matches, coaching academies, referees courses and infrastructural support" - but that did not imply any attempt to buy support.

Football Federation Australia, who were beaten by Qatar in the 2022, contest, said it had been heavily involved in Garcia's investigation.

FFA chief executive David Gallop told Melbourne radio station SEN: "It's a serious development, they're serious allegations and we're looking to see what the response to that will be.

"It's too early to say whether that reopens the door of anything that happened a few years ago in terms of Australia's position but it's a bit of a 'watch this space' at this stage.

"We've been heavily involved in this now for many months in terms of the investigation that Mr Garcia is carrying out. We've got people who've been involved for some time now."