The NC Employment Security Commission is preparing to send the letters this month. The extension increases benefits by up to 20 weeks, to a total of 99 weeks.
Officials say nearly 20,000 of the state's unemployed automatically received the extended benefits, but thousands more may have to wait several weeks so the commission can upgrade its computer system that processes the payments.
North Carolina has lost more than 240,000 jobs in the last two years. The state's unemployment rate was 11 percent in October.