Karlheinz Schreiber speaks with journalists as he arrives at the Toronto West Detention Centre on Sunday. Darren Calabrese/Canadian Press)German-Canadian businessman Karlheinz Schreiber was being flown to Germany on Sunday evening after losing a last-ditch battle to avoid extradition earlier in the day.

Schreiber's lawyer, Eddie Greenspan, was granted permission for a special weekend court appearance to seek an injunction against the federal government's extradition order. He argued that his client should be allowed to stay in his adopted country — where he has been a citizen since 1982 — until at least Tuesday morning so he can file an appeal challenging Canada's extradition treaty with Germany.

But the lawyer for the government told the Superior Court of Justice that this was a frivolous challenge because the treaty was ratified 30 years ago.

In her decision turning down the injunction bid, Superior Court Justice Barbara Conway said: "Mr. Schreiber has travelled a long road in fighting his extradition to Germany. He is now at the end of that road."

Schreiber reported to the Toronto West Detention Centre shortly before 5 p.m. ET, and left Toronto for Germany early Sunday evening, his wife confirmed to CBC News.

Justice Department spokeswoman Geneviève Breton said his flight left Toronto between 8 p.m. and 10 p.m. ET. But she did not provide further details.

In a letter released to CBC, Schreiber said he decided to ask for the emergency hearing after two officials from the federal Justice Department visited him on Friday afternoon. He said they served him at 5:10 p.m. ET with a response to a letter from his lawyer, triggering a process that requires him to surrender himself into custody by Sunday afternoon.

In the letter, addressed to Prime Minister Stephen Harper, Schreiber said he was concerned the visit was timed in a way to preempt any legal moves on his part duringt the holiday weekend.

"It seems obvious that the timing of the service seemed to be designed to prevent me from having access to the courts on a long weekend during which I apparently have 48 hours to surrender myself to the Toronto West Detention Centre after receipt of the minister's letter, as specified in my bail conditions," he said in the letter.

Extradition politically motivated: Schreiber

He also alleged in the letter that Germany's centre-left Social Democrats are using his case as an election issue in a bid to defeat their conservative opponents in next month's election.

Schreiber, a key figure in a political scandal surrounding former German chancellor Helmut Kohl, was arrested in Canada in 1999 under a German warrant seeking his extradition.

Journalists are reflected in the sunglasses of Karlheinz Schreiber as he arrives at the Toronto West Detention Centre on Sunday. (Darren Calabrese/CP Photo)Schreiber, 75, who has both Canadian and German citizenship, is being sought by German prosecutors on bribery and fraud charges as well as charges he evaded income tax on millions of dollars in commissions from arms deals. He was released on bail from a Canadian jail in late 2007.

"Now we have the election coming up in Germany in September, and the Social Democrats won three elections with my case in the past," Schreiber told reporters Sunday just before entering the detention centre. "If I would [return] now that would be the greatest thing. They would start another huge circus and huge investigation and all the previous chancellor Kohl and all the ministers and everybody would be there. And with that, they would think they could win the next election."

Public hearings on his financial dealings with former prime minister Brian Mulroney drew to a close last Tuesday.

The federal government allowed Schreiber to stay in Canada long enough to give evidence at the Oliphant Commission.

"The whole approach is again to get my mouth shut and get me out of the country," Schreiber told reporters.

He also said Justice Minister Rob Nicholson had received a fax from the German authorities urging the extradition to proceed now that the inquiry was complete.

By complying with the request, the federal Conservative government is essentially undermining the re-election efforts of their own conservative counterparts in Germany, who are heading into a campaign next month, Schreiber said.

At the inquiry, Schreiber testified he gave Mulroney $300,000 to lobby the Canadian government to build a light-armoured vehicle plant on behalf of Thyssen Industries. Schreiber said he struck the deal with Mulroney before the prime minister left office, although the money didn't change hands until later.

Mulroney told the commission he accepted $225,000 in cash from Schreiber to promote the sale of those vehicles internationally, but only after leaving politics. He admitted to taking the sum but not reporting the cash payments for income-tax purposes until six years after he started getting them.

Mulroney has described the agreement as one of the biggest mistakes of his life and said Schreiber's allegations are an attempt to stave off his extradition.

The deadline for Oliphant's report to the federal government is Dec. 31.

With files from The Canadian Press