A private association of National Guard members plans to hold its annual conference in Honolulu this year, even though some officials at the Pentagon have questioned the wisdom of meeting in a vacation destination.

About 3,000 to 3,500 people are expected to attend the September convention, said John Goheen, a spokesman for the National Guard Association of the United States. That’s down from the 4,000 who attended last year’s meeting in Reno, Nev., a decline that’s primarily due to fewer defense contractors participating in the trade show part of the conference.

Goheen said there’s a perception that people go to meetings in a tropical environment only to have fun. Some at the Pentagon have privately questioned the choice of location, saying it won’t look good to have people going to Hawaii, he said.

“People get all caught up in the palm trees and the leis and the surfboards, and for some reason they don’t understand it’s a state,” Goheen said.

Most people who attend — officers, retirees and company representatives — pay their own way, he said. Federal money won’t pay for many participants.

Plus, Hawaii is home to the U.S. Pacific Command, which is responsible for U.S. military activity in Asia and the Pacific. This will allow attendees to learn about the region just as U.S. policy is placing greater importance on the area, and will be particularly useful for those who have been focusing their attention and training on Iraq and Afghanistan for many years, Goheen said.

“We can come away learning a little more about the issues of that particular command and the issues of that particular part of the world — which is very different than when you have a conference in Reno,” he said.

Those who come will also have opportunities to network and get to know senior leaders. Last year, Army and Air Force chiefs of staff both attended.

Mike McCartney, president of the Hawaii Tourism Authority, said the state’s strong military presence makes it an ideal location for such conferences. There’s also a growing view that Hawaii is a place for serious meetings, as shown by the success of the Asia Pacific Economic Cooperation, or APEC, summit held in Hono­lulu in 2011, he said.

“Hawaii is more than just a leisure destination — we are a place that can host productive and quality business meetings,” McCartney said in a statement.

The National Guard association was formed in 1878 with the goal of obtaining better equipment and training for state militias. Today, it includes 45,000 current or former National Guard officers.

This year’s conference will be held Sept. 20-23 at the Hawai‘i Convention Center.