President Barack Obama has acknowledged that widespread problems with his new health care law are unacceptable, as the government tries to fix the glitches, The Associated Press said.

Obama is due to make his first health care-focused speech since a cascade of computer problems with "Obamacare" became apparent.

The troublesome introduction of the health care exchanges has been an embarrassment for Obama's signature legislative achievement and could impact on next year's Congressional elections as well as the president's legacy.

The troubles were overshadowed, however, by Republican efforts to delay or cut funds for Obamacare in exchange for reopening the government during the 16-day shutdown which began the same day as health care law was rolled out.

The bill that eventually reopened the government included no substantive changes to the health care law.

Solutions include more staff at call centres where people can apply for insurance by phone and the use of technology experts from inside and outside government to help diagnose the issues.

Nearly a half million applications have been filed through the federal- and state-run exchanges. Users must file applications before they can enroll, in part to find out whether they are eligible for government subsidies.

Administration officials initially blamed a high volume of interest for the frozen screens that many people encountered. Since then, they have also acknowledged problems with software and some elements of the system's design.

Despite the widespread problems, the White House has yet to fully explain what went wrong with the online system consumers were supposed to use to sign up for coverage.