BERLIN  (Reuters) -- A German referee suspected of betting on a German Cup match he was officiating has resigned, the German football association (DFB) said on Saturday.

Robert Hoyzer, 25, was under investigation by the DFB for suspected betting on the result of the first round German Cup tie between SC Paderborn and Hamburg SV last August. The DFB said in a statement that he had resigned on Friday evening.

The regional side surprisingly beat their Bundesliga opponents 4-2. The DFB said it suspected that Hoyzer had sought to influence the result of the game and was considering bringing a charge of unsporting conduct against him.

The suspicion first came to light on Wednesday and the DFB called a hearing for Friday.

Hoyzer, who it said had previously denied the accusations, gave no statement, saying that he was under no obligation to do so after his resignation, the DFB said.

"Regarding other possible affected games, investigations have not been concluded," the DFB said in a statement, adding there was no possibility of revising the result of the Paderborn v Hamburg match.

Hoyzer, a referee on the DFB's books since 2002, had taken charge of 12 second division matches, as well as German Cup and regional league fixtures.

The DFB's co-president, Theo Zwanziger, said he was shocked by the news.

"This is a regrettable and unforgiveable incident.... I assume the issue will be pursued fully... As we see it now, it is a one-off case, which should not lead to general criticism of our referees," he said.

He has called an extraordinary meeting with fellow DFB and Bundesliga officials in Frankfurt on Monday.

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