PHOENIX - Arizona's 2010 immigration enforcement law is being called a lingering hindrance to Phoenix's ability to lure gatherings to its convention center.

Convention center bookings are down by about 30 percent from 2009, while guest bookings in cities with comparable convention facilities are gradually increasing or stable, The Arizona Republic reported Wednesday.

The immigration law known as SB1070 is one of several possible factors, with others including the recession and tighter strings on corporate and government travel.

However, other cities with comparable convention facilities have slowly rebounding or relatively flat guest counts, the Republic reported.

Since the law was enacted, courts have overturned much of it, but the U.S. Supreme Court last year let a key provision take effect.

That provision requires that police officers make a reasonable attempt to determine the immigration status of a person stopped, detained or arrested if there is reasonable suspicion the person is in the country illegally.

After the law was enacted, numerous groups and organizations announced boycotts of the state.

National conferences and meetings are scheduled years in advance, and Phoenix officials said they are just now feeling the full impact on visitation.

"The misperception that our city does not value diversity continues to be an impediment to attracting national convention groups," said Scott Dunn, a spokesman for the Greater Phoenix Convention and Visitors Bureau. "In some cases, the damage from what happened in 2009 or 2010 won't wash ashore until 2013 or 2014."

Though talk of boycotts has largely dissipated, Dunn said three large groups recently told the visitors bureau they were not considering Phoenix for their meetings because of the immigration issue.

City Councilman Jim Waring, a Republican former legislator who supported SB1070, said he thinks any adverse economic impact of the law is overplayed.

"That's a pretty hefty drop-off; to me, that speaks to other challenges," Waring said. "I would be surprised if 1070 played much of a factor."

Councilman Michael Johnson has met with organizations across the country and said many worry about how their members will be treated in Arizona.

"That is still a huge issue that we have," Johnson said. "People really think and feel like that, and that (image is) absolutely not true. People are not being stopped just because of the color of their skin."

Mayor Greg Stanton recently urged a group of event planners to not hold the immigration law against his city.

"What you may have read about our Legislature, don't hold against the rest of us," Stanton said. "The rest of us, we're normal. We like diversity."