US govt shutdown cost economy $US3b: CBO

The US economy is expected to lose $US3 billion ($A4 billion) from the 35-day partial federal government shutdown over President Donald Trump's demand for border wall funding, congressional researchers say.

The cost of the shutdown will make the US economy 0.02 per cent smaller than expected in 2019, a report by the nonpartisan Congressional Budget Office (CBO) said on Monday.

But researchers said more significant effects will be felt by individual businesses and workers, particularly the nearly 800,000 federal employees who went without pay.

Overall, the US economy lost about $US11 billion during the five-week period, the report said. But CBO expects $US8 billion to be recovered as the government reopens and federal workers receive back pay.

The US government reopened fully on Monday. It remained to be seen how lawmakers address border security before the February 15 deadline while avoiding another closure.

Trump had demanded $US5.7 billion towards building his long-promised wall along the US-Mexico border, which he says is necessary to stop illegal immigration, human trafficking and drug smuggling.

Democrats oppose any money for a wall but say they back additional funding for security measures along the border.