Updated: 6:18 p.m.

To the chagrin of some Democrats, Senate Majority Leader Harry Reid (D-Nev.) today moved to limit amendments on a House-passed JOBS Act and set up two procedural votes for Tuesday — the only amendments expected to be offered to the measure.

“I am very concerned about that,” said Sen. Jeff Merkley (D-Ore.), who fears a provision in the House bill allowing startup companies to raise capital on the Internet opens up investors to potential stock scams.

He said the Senate should have been allowed to work its will and improve “a deeply flawed House bill.”

Reid’s move is an effort to pass the House measure as quickly as possible. Because Reid used a maneuver known as “filling the amendment tree,” no other amendments to the bill will be allowed. Leaders are trying to keep it as close to the House-passed version as possible.

Until recently, Democrats, including Sens. Jack Reed (R.I.), Carl Levin (Mich.) and Mary Landrieu (La.), were working on a Democratic version of the House bill that Reid had told reporters he was planning to bring up instead.

The unrest even extends into leadership. Majority Whip Dick Durbin (D-Ill.) also supported a more consumer-friendly Senate version, speaking out against the bill on the Senate floor Wednesday.

Democrats were pressured by House and Senate Republicans to take up the House version after the measure passed 390-23 last week. President Barack Obama’s endorsement of the House measure also put pressure on the Senate.

“President Obama has endorsed this bill very publicly and thus this is a measure the Senate should consider expeditiously and pass in short order,” Reid said on the Senate floor today.

Other Democrats were also disappointed. Sen. Benjamin Cardin (Md.) said he had some amendments he wanted to offer but said he understands that some Senate Democratic leaders want to quickly pass the bill.

“I am disappointed that we are not going to have a more open process on it, but I understand where the leaders are coming from,” Cardin said, adding that he expects to back the bill.

The first vote Tuesday will be whether to cut off debate on a Democratic substitute package that includes many of the changes some Democrats were hoping to make as part of a Senate version of the House bill. Offering it as an amendment, rather than the underlying bill, often makes it harder to prevail on the Senate floor.

Outside groups that were critical of the House bill expected the Senate to take up its own version.

“I hope they are not disappointed,” Levin said, adding that he was grateful that their substitute would get a vote. He declined to say if it would win the 60 votes needed to pass. It is unclear if Republicans will vote in favor of the Democratic plan. Seven Republicans would need to break ranks and join with the 53 Democrats for the amendment to pass.

The Democratic proposal includes a raft of consumer protection provisions that Democrats argue would strike the right balance between easing access to capital and protecting consumers. The proposal also includes a provision to reauthorize the Export-Import Bank, which is designed to facilitate the purchase of U.S. exports to international buyers.

The second vote will be to cut off debate on an amendment to the House package that would only reauthorize the Export-Import Bank. The amendment is bipartisan, and with Senate Banking ranking member Richard Shelby (R-Ala.) co-sponsoring the proposal, Republicans could be enticed to provide the 60 votes needed to cut off debate on the amendment.

Supporters of the proposal argue that failure to reauthorize the bank would put U.S. businesses at a disadvantage to their foreign competitors. The bank’s authorization expires at the end of May, but it will hit its loan limit in about two weeks.

The conservative Club for Growth came out against the Export-Import Bank amendment. The amendment, the group said, would increase the bank’s power by a whopping 40 percent, expanding its loan capital limit from $100 billion to $140 billion.

“The Export-Import Bank’s actions are nothing more than market-distorting subsidies that pick winners and losers in the private sector. Market forces should dictate trade flows, not bureaucrats and politicians,” the group noted in a statement.

It is also unclear, if the Senate adopts the bank amendment, what the bill’s prospects would be in the House because of possible opposition from conservatives in that chamber.