It cost the federal government more than $300 million for outside contractors to set up the Obamacare website that has had so much trouble in its first three weeks of operation.

Most of that money has gone to six contractors that together have received more than $200 million in taxpayer funds, with the biggest single contractor receiving $88 million.

Overall, the government has spent $394 million setting up the website and the exchanges through which the public can buy health insurance, according to a report earlier this year from the General Accountability Office, a government watchdog. While not all the money went into the troubled websites, most of it did.

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The largest contractor is CGI Federal Inc., the U.S. unit of a Canadian firm CGI Group (GIB). It received $88 million through last March 31. Its original $93.7 million contract runs through December, with three one-year option periods still possible.

A company spokeswoman said the terms of the contract prevent it from speaking about the details of its work.

Quality Software Services Inc. received $55.1 million to set up the data hub, according to the GAO report, while National Government Services Inc. a unit of WellPoint (WLP), received $31.6 million for a consumer call center and providing premium aggregations. Neither company responded to a request for comment.

The MITRE Corp., which GAO lists as receiving $22 million for project management and information technology security, also said it could not comment on its contract.

Genova Technology received $16 million for information technology and Terremark Federal Group, a unit of Verizon (VZ), received $15.5 million for cloud computing services. Neither of those companies had a comment on their contracts.

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The problems with the site are getting increased attention in Washington now that the federal government shutdown has ended. President Obama said Monday that there is "no excuse" for the problems many people are having signing up for coverage on the website. He said there would be a "tech surge" of additional outside help to correct the problems.

The House Energy and Commerce committee has scheduled a hearing Thursday on implementation problems. Numerous Republican members of Congress are calling on Health and Human Services Secretary Kathleen Sebelius to resign or be fired.