Protesters rally in Atlanta at the capitol to denounce support bills that aim to crack down on illegal immigration. AP Photo/John Amis

ATLANTA - A federal judge in Atlanta on Monday put on hold some of the most controversial parts of Georgia's new anti-illegal immigration law pending the outcome of a lawsuit challenging the measure's constitutionality.

In a 45-page ruling issued Monday, U.S. District Court Judge Thomas Thrash preliminarily enjoined the state from enforcing two provisions in the law.

One of those provisions would empower police to investigate the immigration status of certain suspects. The other would punish people who knowingly transport or harbor illegal immigrants or encourage them to come here.

The judge said in his ruling that the civil and immigrant rights groups who are suing to block the law have shown they can prevail on their arguments that these provisions are pre-empted by federal law.

State officials indicated last week they would appeal to the 11th Circuit Court of Appeals in Atlanta if Thrash were to grant the preliminary injunction.

Also Monday, the judge threw out some of the arguments in the lawsuit from the American Civil Liberties Union and others. Among the arguments he dismissed were ones that say the new law violates people's rights to travel and their protection against unlawful search and seizure.

Georgia's immigration law was to have been phased in over the next few years.

The provisions empowering police to arrest illegal immigrants, and barring people from transporting, harboring and luring them to the state, would have taken effect Friday.

Another provision to take effect Friday calls for up to 15 years in prison and up to $250,000 in fines for people who use fake identification to get a job in Georgia.

Additionally, a seven-member Immigration Enforcement Review Board would be established to investigate complaints about local and state government officials not enforcing state immigration-related laws.

Government officials who violate state laws requiring cities, counties and state government agencies to use E-Verify could face fines of up to $10,000 and removal from office.

Also, the state Agriculture Department would be directed to study the possibility of creating Georgia's own guest-worker program. Some Georgia employers have complained the federal government's guest-worker program is too burdensome and expensive.

On Jan. 1, state and local government agencies have to require people applying for public benefits - such as food stamps, housing assistance and business licenses - to provide at least one "secure and verifiable" document, which could be a state or federally issued form of identification. Consular matriculation cards would not be accepted.

Also on this date, Georgia businesses with 500 or more employees would be required to use the federal E-Verify program to determine whether their new hires are eligible to work legally in the U.S.

The deadline would be July 1, 2012, for businesses with 100 or more employees but fewer than 500; and July 1, 2013, for firms with 11 to 99 employees. Businesses with 10 or fewer employees are exempt.