DENVER -- The Colorado State Patrol is reporting its immigration unit has detained nearly 800 suspected illegal immigrants and investigated 33 human smuggling cases since it became operational last year.

"I think the number of we've actually arrested is in the 180 range," said Col. Mark Trostel from the Colorado State Patrol.

"That's a significant amount especially when you consider you have some individuals that have come here illegally and have been involved in criminal activity, anything from sexual assault, child abuse, robbery," Trostel told 7NEWS Reporter Lane Lyon.

The figures were released Friday.

The Immigration Enforcement Unit has 23 troopers around the state. Their work is limited to smuggling, trafficking and immigrations violations as they are encountered in traffic stops on the state's highways.

Lance Clem with the Colorado State Patrol told 7NEWS "a substantial number of the suspected illegal immigrants that were stopped were arrested on drug and DUI charges."

Clem said "the unit has accomplished a lot more than they expected. Their numbers continue to be impressive."

The special enforcement unit has been in operation since July 1, 2007.

Patrol Sgt. Todd James said the troopers get four weeks of special training. He said the 23 officers aren't enough to patrol the entire state.

The Legislature established the unit in 2006, authorizing the patrol to hire additional troopers so its other duties would not suffer.

Colorado was the 17th state to form such a unit.

Interstate 25 and Interstate 70 are major route for human smuggling, so many believed that it only made sense that troopers who patrol the interstate are trained to crack down on the illegal activity.

Before, CSP troopers had to call an Immigrations and Customs Enforcement officer to the scene to determine if a person they have stopped is here illegally or not. Now the troopers can do that on their own.

There are some critics of the program, including the Denver-based non-profit group, Rights For All People.

Executive Director Lisa Duran said local law enforcement should focus on other public safety issues and not enforce federal immigration law.

"If local law enforcement can't focus on violent crimes, which is where I think most of community would want them to, then we're all less safe," Duran said.

Trostel stood behind the program and added problems with illegal immigration in the state outweigh resources available from CSP, ICE or the Department of Corrections.

Trostel told 7NEWS the impact being made is a “thimble full in a five-gallon bucket of water.”

A bill to double the number of troopers in the unit failed in the state legislature this year, according to Trostel.

"We're taking some of the most serious offenders off the highways and that's a plus, but a lot more could be done if more resources were available," Trostel said.