Travel groups and airlines are warning of potential disruption as the US federal government partially shut down after lawmakers failed to reach a deal on funding the Department of Homeland Security (DHS).

Several groups, including Airlines for America, stated in a joint statement that without a deal, the risk of unscheduled absences by Transportation Security Administration workers increased, resulting in flight delays and longer wait times.

Travellers and the US economy cannot afford to have essential TSA personnel working without pay, they elaborated.

A partial government shutdown began at midnight after Congress failed to pass a bill to fund DHS operations.

In exchange for a funding deal, Democrats had been advocating for more restrictions on US Immigration and Customs Enforcement (ICE), which will not face significant impacts from the shutdown due to previous funding provisions.

Democrats have been pushing for reforms following the controversial killings of two Minneapolis residents by federal agents during immigration protests. Proposed changes include enhanced identification for immigration officers and prohibitions against wearing masks during raids.

On Thursday, Senate Democrats blocked two funding bills, citing the lack of immigration reform provisions as a key issue. The last funding measure had only secured two weeks of operation for the DHS.

President Donald Trump indicated uncertainty about reaching an agreement, emphasizing the need to protect law enforcement personnel.

The shutdown affects several agencies under the DHS, including the TSA and Coast Guard. Previous shutdowns, particularly last year's, led to extensive travel chaos, but experts predict this shutdown might not have as severe an impact on air travel, as the Federal Aviation Administration is fully funded for the year.

However, TSA workers, who are also under the DHS, may have to cope with delayed payments, which could lead to higher absenteeism and longer lines at airports. The shutdown's full scope remains uncertain as Congress is slated to take a recess, potentially prolonging negotiations.