The controversy over President Obama’s back-to-school speech has moved to the phone lines.

School districts around the country are ringing parents with robocalls to inform them of the speech and give them the opportunity to prevent their children from hearing it. Obama plans to give a motivational speech Tuesday from an Arlington, Va., high school.

The announcement of the speech sparked complaints from some conservatives who said the president is using the platform to “indoctrinate” students and that the related activities and materials provided to schools by the Department of Education are designed to solicit support for the president. White House officials have said the speech is not policy oriented but rather a way to encourage kids to study hard and stay in school.

Some parents have expressed their surprise at receiving the calls, which are often reserved for notifying parents of school closures or emergencies.

For example, the Cherry Creek School District in an affluent suburb of Denver, Colo., initiated calls to parents Thursday indicating the speech would be shown on a class-by-class basis and asking parents to call the school if they did not want their children to watch the speech.

Sonya Unrein, whose daughter attends high school in the district mentioned the call on the microblogging site Twitter. She said she is perplexed by the controversy surrounding the speech.

“If the president were giving his health care speech to school kids, there might be a reason to think that he was using a platform for political purposes,” she wrote in an email. “But my understanding is that he plans to talk about achievement and studying and all the things we as a society purport to value. How can kids understand the issues of our times if we shield them from experience?”

Parents in school districts in Texas, Louisiana and South Carolina have also gone online to discuss receiving similar calls from the local school district, said Shaun Dakin, chief executive and founder of the National Political Do Not Contact Registry, a nonprofit advocacy program.

Political campaigns and activist groups commonly use robocalls to contact voters and spread messages. Schools began using automated calls, often referred to as parental notification systems, several years ago, spurred by the shooting at Columbine High School and the attacks of Sept. 11, 2001.

Dakin said he has not seen any evidence that conservative or other political groups are initiating calls.

Mary Kusler, a lobbyist for the American Association of School Administrators, said most school districts have parental notification systems that are becoming increasingly sophisticated, allowing administrators to contact parents by phone, email or text message.

“They’re trying to quell any concerns that parents may have,” she said. “It’s a proactive strategy, rather than waiting to hear from parents about it.”

She said that school districts have been inundated with calls from parents. The Fort Smith, Ark., district, for example, received 2,000 calls about the speech on Thursday alone, she said.

Supporters of the speech say they don’t see a reason to be alarmed.

“When is someone going to stand up and say it is ridiculous that we’re asking for permission to opt out of a speech about doing well in school?” said Andrew J. Rotherham, co-founder of the think tank Education Sector. “The compelling message of the speech is, if you drop out of school you drop out on your country.”