WASHINGTON: The US Senate finally took up the $1.9 trillion Covid relief package Thursday but a brazen ploy by opponents -- reading the entire 628-page bill aloud on the chamber floor -- promptly gummed up the action.

President Joe Biden has pushed hard to get his top legislative priority through Congress, and it narrowly cleared the House of Representatives last week.

But instead of the upper chamber launching directly into debating the measure aimed at helping millions of families and boosting a crippled economy, Republicans halted the process for hours by demanding that clerks recite every word of the ambitious plan.

Republicans already appeared united in opposing the proposal over its high cost, and lawmakers braced for marathon days that will include up to 20 hours of debate and a lengthy list of amendments that will force contentious votes before the bill's final passage.

But Biden has been desperate to implement its key elements, including direct checks of up to $1,400 for most Americans, funding for vaccines, expanded unemployment benefits, resources to help open schools quickly and money to hard-hit businesses and communities.

With the chamber deadlocked at 50-50, Vice President Kamala Harris broke the tie to allow debate to begin.

The process immediately hit a snag when Republican Senator Ron Johnson called for a full reading of the coronavirus package.

The recitation, estimated to take about 10 hours, proceeded uninterrupted deep into Thursday night with clerks taking turns reading the dry, technical language in a monotone that threatened to put lawmakers and others to sleep.

Debate on the package, which Democrats argue is the best way to combat the pandemic, may only begin well after midnight.

Bill readings are almost always dispensed with at the start to allow for debate, but Johnson saw it as way to register his frustration over the massive outlay of federal spending.

"I feel bad for the clerks that are going to have to read it, but it's just important," said Johnson, who has already faced criticism this week for suggesting the deadly January 6 US Capitol riot was not an "armed insurrection."

"Why are we authorizing another $1.9 trillion when we still have a trillion dollars sitting on the sidelines" unspent from the previous pandemic relief bills? he told reporters.

"It's actually hard to spend this much money."