Karlheinz Schreiber is facing charges of bribery, fraud and income tax evasion in Germany. (Tannis Toohey/Canadian Press)

German-Canadian businessman Karlheinz Schreiber is recovering well in an Ottawa-area hospital after undergoing gallbladder surgery on Tuesday night, according to his wife.

CBC News learned on Tuesday that Schreiber was admitted to hospital in the afternoon after complaining of stomach pain for several days.

He is being treated for an inflammation of the gallbladder and gallstones.

Barbel Schreiber said her husband had been experiencing pain since Friday, but refused to go to hospital before hearing Brian Mulroney testify at an inquiry looking into Schreiber's financial dealings with the former prime minister.

In an interview with CBC's Don Newman on Tuesday morning, Schreiber acknowledged he had "something with the stomach at the moment." But he went on to deny the condition had any connection to the inquiry.

"I ate something wrong," Schreiber said.

Schreiber spent Tuesday morning at the inquiry but didn't return for the afternoon session, instead visiting his doctor.

The arms lobbyist has attended almost every day of the inquiry, headed by Judge Jeffrey Oliphant of Manitoba's Court of Queen's Bench.

Schreiber's surgery went well, his wife said, but it isn't yet clear when he will be released from hospital. He won't be present when Mulroney continues his testimony on Wednesday, Barbel said.

Next week, Schreiber is scheduled to take the stand for his sixth day.

Cash payments to ex-PM at issue

The inquiry is probing the three cash payments Mulroney received from Schreiber in 1993 and 1994 in three hotel rooms.

Schreiber has said he paid Mulroney $300,000 to lobby domestically on behalf of the Bear Head project — a plan to establish a light armoured vehicle plant in Nova Scotia, and then Quebec.

But Mulroney has said he was paid $225,000 in three instalments and that the money was payment for his efforts to promote the vehicles internationally on behalf of the German company Thyssen.

Schreiber was arrested in 1999 in Toronto on charges of bribery, fraud and income tax evasion in Germany — charges Mulroney said he knew nothing about. Schreiber is facing extradition to Germany.

With files from The Canadian Press