California's health insurance exchange said more than 400,000 people have signed up for health plans ahead of Monday's enrollment deadline as part of the Affordable Care Act.
The Covered California exchange said the latest figures are based on preliminary data through Sunday, when about 27,000 people picked an insurance company. Enrollment Friday was even higher, at 29,000 people, according to the exchange.
"We very much expect today will be a big day," Peter Lee, executive director of Covered California, said Monday. "We are seeing huge interest online."
The state's latest official figures were 156,000 enrolled in health plans through Dec. 7, and an additional 179,000 people who had qualified for an expansion of Medi-Cal, the state's Medicaid program.
State officials declined to give an updated enrollment figure for Medi-Cal.
The Obama administration announced Monday that it was giving consumers in 36 states who are using the federal exchange an extra 24 hours, through Christmas Eve, to complete an application to accommodate high demand.
California officials said they are sticking with the Dec. 23 deadline, but they vowed to help anyone who starts an application Monday to get coverage effective Jan. 1. They acknowledged that some consumers are running into website glitches and long wait times on the phone.
"We will help people get across the finish line who have started an application today," Lee said. "If you have made a good-faith effort to get started, you can finish it [Tuesday]."
If people don't get through, open enrollment under the federal healthcare law continues through March 31.