A monthlong sand-replenishment project undertaken to widen a stretch of Waikiki Beach will be more disruptive than initially planned, officials said Thursday.

But most of the 2.5-mile beach will remain open and only a portion will be periodically blocked in the mornings, as three trucks and a bulldozer are used to deposit and grade the sand starting March 12, state and visitor industry officials said.

"We’re not closing the beach," said Jerry D. Westhaver, general manager of the Hyatt Regency Waikiki Resort & Spa.

Initially the sand brought onshore from nearby shoals was going to be transported by an underground pipe to replenish 1,730 linear feet of beach between the Duke Kahanamoku Statue and the Royal Hawaiian Hotel groin.

But the method of air-blowing sand to move it through the pipe was taking longer than projected, so the contractor will turn to Plan B: using trucks to haul sand along the beach.

Work will take place from 7 a.m. to noon, seven days a week, from March 14 through April 14. In the afternoons, people will have unrestricted use of the entire beach.

Hotel officials said that in the project area, people will be able to reach the ocean from the hotels in the mornings along designated paths, directed by construction employees.

Under the original plan, only a 200-foot-wide section of beach would have been closed at a time, with the rest of the beach open as the underground pipe transported sand.

William Aila, director of the state Department of Land and Natural Resources, said he doesn’t know why the rate of sand transport through the pipe was slower than projected.

He said similar projects have worked on the mainland.

Aila said the $2.2 million cost of the project would not change.

Rick Egged, president of the Waikiki Improvement Association, said the sand replenishment project is needed to widen Waikiki Beach to its 1985 width.

Egged said a study pegged the economic value of Waikiki Beach at about $2 billion a year.

"It’s essential that we continue to maintain this really valuable asset," he said. "We believe the project is a positive one."

Egged said the plan still allows people to have time on the beach every day.

Hotel officials said that since the hotels are consistently above 80 percent occupancy, there was no good time to replenish the beach.

Aila said he chose the March-April period to avoid summer south-swell conditions.