WASHINGTON: US lawmakers have cautiously welcomed a massive free trade deal sealed by 12 Pacific rim countries, but the accord faces intense scrutiny in Congress which will vote on its ratification in 2016.

Republicans, whose party controls both the Senate and House of Representatives, broadly favor free trade, but their key lawmakers reserved judgment Monday, stressing they will need time to comb through the Trans-Pacific Partnership.

Some predicted it will be a tough test for President Barack Obama, whose own Democrats are split on whether to support the accord.

“While the details are still emerging, unfortunately I am afraid this deal appears to fall woefully short,” said Senate Finance Committee chairman Orrin Hatch, a crucial Republican voice on international trade.

“It’s now time for Congress and the public to examine the details of the TPP and assess whether it will advance the nation’s interests,” said the committee’s top Democrat, Senator Ron Wyden.

“I am reserving judgment until I am able to review the final text and consult with my colleagues and my constituents,” said House Ways and Means Committee chairman Paul Ryan.

“Only a good agreement — and one that meets congressional guidelines in the newly enacted Trade Promotion Authority (TPA) — will be able to pass the House.”

Ryan, Hatch and Wyden were key to brokering TPA, which passed in June and provides for the US Congress to vote up or down on the trade accord, but without the ability to amend it.

While TPA provided the White House with fast-track authority to negotiate the trade accord, the process will take months, pushing the vote to next year and into the heat of the US presidential primary contests.

The president must formally notify Congress of his intent to sign the deal at least 90 days before doing so.

The administration must submit reports on the accord, and Congress must vote on whether to allow its implementation.

The most strident opposition will likely come from liberal Democrats who fear the deal would weaken some US industries and erode American jobs.

They revolted in June, opposing fast-track authority and forcing Obama into the rare position of relying on Republican rivals to pass TPA.

“This agreement follows failed trade deals with Mexico, China and other low-wage countries that have cost millions of jobs and shuttered tens of thousands of factories across the US,” said Senator Bernie Sanders, an independent challenging Hillary Clinton for the Democratic presidential nomination.

House Democrat Louise Slaughter has warned she will be working with the Canadian and Australian parliaments to derail the deal, which she said would allow the import of unsafe foods and restrict access to affordable medicine.