(Adds attorney-general comments)

JERUSALEM, May 18 (Reuters) - Israeli police plan to question Prime Minister Ehud Olmert for a second time, a spokesman said on Sunday, as part of a bribery investigation that could force him from office.

"The official request has been handed over to the prime minister's lawyers and we are waiting for a response regarding the time and place for questioning," police spokesman Micky Rosenfeld said.

Olmert's office had no immediate comment.

Police first questioned Olmert on May 2 about money he received from New York financier Morris Talansky. Investigators have since raided offices at Jerusalem's city hall and the Ministry of Industry, Trade and Labour, both of which Olmert once headed.

Olmert said earlier this month he took cash from an American businessman, but has denied any wrongdoing, saying the money was used for campaign funding. Olmert said he would resign if indicted.

Israeli Attorney-General Menachem Mazuz said on Sunday the investigation would not be finished anytime soon.

"I am not sure we will make any decisions in the the coming weeks. It seems a bit unrealistic," Mazuz told Israel's Channel Two news.

"We are going through a painful process, a sort of cleaning process that in my opinion will definitely bring a cleaner reality," Mazuz said.

Olmert, who once described himself as "indestructible", has survived several earlier corruption investigations. (Writing by Ari Rabinovitch; Editing by Matthew Jones)

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