GOP lawmakers on Friday expanded the Child Tax Credit that helps low-income families in a bid to persuade Florida Sen. Marco Rubio to support their tax reform bill after he threatened to vote no over the issue.

South Dakota Rep. Kristi Noem, one of the Republicans working on a final bill, predicted that Rubio would get back on board after the change.

“I believe that we’re in a good spot and should be able to earn his support,” she told The Washington Post

A Rubio spokeswoman said he was eyeballing the final measure and would decide whether it met his demands.

Congressional Republicans were set to unveil their sweeping tax package Friday amid uncertainty about whether they have the votes to pass it in the Senate and deliver to President Trump his first major legislative victory.

At the White House, Trump said he was confident that Congress would pass the legislation as early as next week.

The package would give generous tax cuts to corporations and the wealthiest Americans — Trump among them — and more modest tax cuts to low- and middle-income families.

“We’re putting in a tremendous child tax credit and it is increasing on a daily basis,” Trump said. “I think that we are going to be in a position to pass something as early as next week which will be monumental.”

Members of a House-Senate conference committee were signing the final version of the legislation Friday.

They have been working to blend different versions of the tax package passed by the House and Senate.

Senate Republicans could still pass the package without Rubio’s vote, but they would be cutting it extremely close. An original version was approved 51-49 — with Rubio’s support.

The Senate turmoil erupted after a key faction of House Republicans came out in favor of the bill, boosting its chances.

Members of the conservative House Freedom Caucus predicted the vast majority of their members would support the package.

The up-and-down turns came after House and Senate Republican leaders forged an agreement in principle on the most sweeping overhaul of the nation’s tax laws in more than 30 years.

Republican leaders predicted swift passage next week, sending the bill to Trump for his signature.

The tax package would double the per-child tax credit from $1,000 to $2,000.

The bill makes a portion of the credit — $1,100 — available to families even if they owe no income tax.

They would receive the money in the form of a tax refund, which is why it’s called a “refundable” tax credit.