The news magazine -- which in October broke the story alleging Germany bought votes to secure hosting rights for the tournament -- said it has seen a contract detailing perks that the Trinidad and Tobago official and the association he headed would be given by the German football association (DFB).
Warner was president of the North American, Central American and Caribbean Football Confederation (CONCACAF), and he was among an initial group of 14 people indicted last May on racketeering, bribery and money laundering charges by the US Attorney General.
The DFB has admitted to the existence of a deal but has said it was only a draft.
Der Spiegel said that incentives offered by Germany to the ex-CONCACAF chief included 1,000 World Cup tickets of the most expensive category that Warner would be able to sell for hundreds of thousands of dollars.
A "contact person" would get $240,000 for the deal, according to the report.
In addition, $4 million worth of merchandising including Adidas footballs, bags and shoes would be sent to the Caribbean.
Bundesliga giants Bayern Munich were also allegedly involved.
Franz Beckenbauer was the club's president at the time, and under the alleged contract, Bayern were expected to train for three weeks every year with a CONCACAF team.
The DFB would take charge of the printing of tickets for up to eight qualification games, as well as the production of 30,000 Trinidad and Tobago flags.
The flags would be picked up by a member of Warner's entourage, with the first-class flights to be paid for by the DFB.
The magazine said the contract was "supposedly not implemented", but that the DFB had been hit with a bill for the production of Trinidad and Tobago flags and a separate one for the printing of tickets for a qualification game between Trinidad and Panama.
Both bills date to 2000, the year the hosting rights of the 2006 World Cup were awarded to Germany.
The DFB had admitted to the existence of a draft deal with CONCACAF that was signed by Beckenbauer, after German daily Bild in November said the agreement was aimed at buying votes.
Germany beat South Africa by 12 votes to 11, with one abstention, to win the right to host the tournament.
Der Spiegel had reported in October that Germany had paid 6.7 million euros ($7.4 million) to FIFA to buy votes in the bid.
German authorities launched an investigation into the allegations and German police raided the offices of the German Football Federation (DFB) in November.
Prosecutors said they were launching a tax probe against three top officials at the federation, but could not pursue accusations of corruption because the statute of limitations on graft had expired.
Both former DFB chief Wolfgang Niersbach and Beckenbauer have denied any wrong-doing in connection with winning the right to host the tournament.