A construction permit the State Ports Authority needs to build its new cruise ship terminal in downtown Charleston will be the focus of a public hearing this month.

The Office of Ocean and Coastal Resource Management will hold the forum April 18 starting at 6 p.m. in Sterett Hall Auditorium on the former Navy base in North Charleston. The address is 1530 7th St.

The SPA filed for a permit last month to drive five pilings in a so-called critical area of the waterfront where development is regulated. The maritime agency said the pilings will support the elevator and escalator systems it must install inside the terminal to comply with the Americans with Disabilities Act.

The application drew more than 30 requests for a public hearing, or about 10 more than required, a spokesman for the Office of Ocean and Coastal Resource Management said Tuesday.

The $35 million terminal is proposed for the north end of Union Pier, where the SPA plans to renovate an existing warehouse known as Building 322. The revamped structure would replace the existing, aging terminal farther south, near the foot of Market Street.

SPA representatives plan to attend the hearing.

“This is a crucial step as we continue moving forward relocating the cruise business to Building 322,“ said spokeswoman Allison Skipper.

The Coastal Conservation League, which is opposed to the site of the new terminal, is urging its supporters to attend.

The Charleston-based league, along with the Charleston Preservation Society and two neighborhood associations, want the SPA to consider other options. The state agency has said Union Pier is the best location for its cruise business.

If approved, the new passenger terminal is expected to be ready in the second half of 2013, or about nine months later than the previous estimate.

The SPA has said the project has been held up by the city’s lengthy architectural review process, which could come to a close next week. The board in charge of approving or rejecting the design will cast its final vote on the project Wednesday.

Contact John P. McDermott at 937-5572.