By Jim Forsyth

SAN ANTONIO (Reuters) - There are no boots on the ground at the newest port of entry between Mexico and Texas, which is under construction on the Rio Grande in the remote Big Bend National Park.

That's because people who are crossing into and out of Mexico will show their papers to a machine when it opens in the spring.

"This port of entry will leverage cutting-edge technology that we have and increase security in the area," said Roger Maier, Customs and Border Protection spokesman in Laredo.

The west Texas port of entry, the first unmanned border crossing with Mexico, sits along the Rio Grande across from the hardscrabble Mexican town of Boquillas del Carmen, and is more than 100 miles away from the nearest major crossing, at Presidio, Texas,

Maier said that for decades, tourists to Big Bend who traveled across the Rio Grande on rowboats to have what he dubbed the "Mexican experience" eating tacos, drinking Mexican beer and riding burros in Boquillas del Carmen, served as the Mexican town's main source of income.

Artists and makers of handmade goods sold products to the tourists who came over from Texas.

But the informal boat crossings came to an end after the September 11 attacks on New York and Washington, and the occasional whitewater rafting trip down the Rio Grande has not been enough to fuel the Boquillas del Carmen economy. Mexico has been angling to reopen the crossing.

Maier said the new crossing would include a robotic camera that will scan a visitor's documents, and Border Patrol agents at a post a mile away will keep an eye on the port of entry by camera. He said that agents would descend on the remote entry port if they noticed any unauthorized visitors.

"I see no problem with this. The bad guys won't be crossing there over to this side," said Michael Vickers, President of the Texas Minuteman Civil Defense Corps, a civilian border patrol group that says it seeks to secure the U.S. border against unlawful entry.

Bill Brooks, another Customs spokesman, said the crossing would also relieve people who have business in Boquillas del Carmen of having to travel 200 miles out of their way to cross the border.

He said the plan was to have checkpoints, which are common for motorists in south Texas, on the paved roads leading through and out of the park, noting that unmanned crossing points have been used along the U.S. northern border with Canada for years without incident.

"This port of entry will only function during hours when Big Bend Park personnel are present," Maier said.

He added that the plan was to beef up the presence of Border Patrol agents and Park Rangers in the sprawling park, which is known for its remoteness, wild scenery and spectacular canyons leading down to the Rio Grande.

(Editing by Cynthia Johnston)