LASHKAR GAH, Afghanistan, Aug. 25 — Afghanistan produced record levels of opium in 2007 for the second straight year, led by a staggering 45 percent increase in the Taliban stronghold of Helmand Province, according to a new United Nations survey to be released Monday.

The report is likely to touch off renewed debate about the United States’ $600 million counternarcotics program in Afghanistan, which has been hampered by security challenges and endemic corruption within the Afghan government.

“I think it is safe to say that we should be looking for a new strategy,” said William B. Wood, the American ambassador to Afghanistan, commenting on the report’s overall findings. “And I think that we are finding one.”

Mr. Wood said the current American programs for eradication, interdiction and alternative livelihoods should be intensified, but he added that ground spraying poppy crops with herbicide remained “a possibility.” Afghan and British officials have opposed spraying, saying it would drive farmers into the arms of the Taliban.