PORTLAND — Construction projects at the Oregon Zoo have been delayed and costly, raising doubts that the zoo will be able to handle multiple projects funded by a $125 million bond voters approved last year, according to an audit.

Auditor Suzanne Flynn said the bond program is at risk unless Metro — the government and planning body for the three-county Portland region — coordinates spending and construction schedules with a comprehensive master plan.

She said the nine projects planned under the bond measure are complex, and the zoo will be hard-pressed to assure the safety of guests and proper care for animals during a decade of construction.

Flynn’s report, released Thursday and obtained by The Oregonian newspaper, found no evidence of fraud.

Scott Robinson, Metro’s deputy chief operating officer, said Flynn’s assessment is accurate. The regional government has hired a bond program manager, a construction manager and a bond planner to take charge of the projects.

An Oregon Zoo Bond Advisory Committee, staffed with community construction, land-use, animal care and facilities experts, was appointed in July to provide additional oversight.

Flynn conducted the audit between March and August, examining five years of project spending.

Her report found that the recently opened Predators of the Serengeti exhibit, which brought lions back to the zoo, had a $1.6 million cost overrun that wasn’t reported until construction was almost done. The 2007 Cascade Canyon project — which linked the mountain goat, bear, cougar and bobcat exhibits — cost $400,000 more than expected.

With both projects, the zoo began construction with designs that would cost more to build than was budgeted, Flynn said in the audit.

For example, the zoo budgeted $320,000 for architectural and engineering services on the Predators of the Serengeti project when it had already issued contracts for $400,000. At one point, four zoo and Metro officials signed off on spending $400,000 for fencing the Serengeti exhibit, even though the project budget contained no money for fencing.

“This indicated to us that an important internal control was missing,” Flynn said in the audit.

More than 1.6 million people went through the gates of the Portland zoo during the fiscal year that ended June 30.