Lawmakers are running out of time to prevent another partial shutdown of the U.S. government. Goldman Sachs' chief economist, Jan Hatzius, predicts a shutdown lasting two to three weeks starting Oct. 1.

"A government shutdown this year has looked likely for several months, and we now think the odds have risen to 90%," said Hatzius.

Hatzius stated in a Wednesday note that despite the possibility of a last-minute deal, there hasn't been significant progress nor ample time remaining, Fortune reported,

He believes that the shutdown could last several weeks due to the build-up of political pressure from delayed military pay dates and a decline in essential operations. A Nomura economics team supports Hatzius's view, also suggesting a potential longer shutdown.

Lawmakers' only option to prevent a shutdown is passing a short-term funding extension, a "continuing resolution" or CR. However, Hatzius warns that the current CRs being pushed by the Senate and House include controversial provisions making their passage unlikely.

A partial government shutdown could affect the salaries of up to four million federal workers and cut various services. However, mandatory spending programs like Medicare, Medicaid, and Social Security are expected to remain unaffected.