Most notably, such companies want to cut or delay massive taxes that would raise tens of billions of dollars over the next 10 years to fund the healthcare reforms.

Other health industries, such as pharmaceutical and biotech companies, however, oppose even minor tweaking after making favorable deals with lawmakers.

The U.S. House of Representatives and the Senate have each passed bills that would expand access to health insurance. The two chambers must still work out differences between the bills in the coming weeks, giving lobbyists an opening to secure last-minute changes although major revisions are unlikely.

Healthcare companies wouldn't be lobbying so hard right now if they didn't feel like they had a chance to make some changes, said John Shepard, a senior healthcare analyst at the Washington Research Group. In terms of specific details, the industry is trying to do a lot of work to make those come out more in their favor.

Health insurers in particular face up to $225 billion in costs through 2019, according to America's Health Insurance Plans (AHIP) President Karen Ignagni, insurers' top lobbyist.

The most significant tax -- a $70 billion, 10-year levy in the Senate bill -- would raise costs for individual and small group coverage, she said. Insurers want to delay it until 2013 or 2014 and spread it more broadly across the industry.

Ignagni, whose group represents Aetna Inc and Humana Inc, among others, said she was encouraged by signs lawmakers were considering timing issues and very optimistic about how that thinking is proceeding.

AHIP also wants to remove limits over how much money insurers could devote to medical care versus profits and other administrative spending, known as a medical-loss-ratio.

Device makers, too, are pressing lawmakers over their tax. Companies such as Boston Scientific Corp and Medtronic Inc face an industry-wide tax of $20 billion through 2019, half the amount lawmakers originally floated.

Lobbyists so far not only halved the device fee but delayed it to 2011. The Advanced Medical Technology Association (AdvaMed) still seeks a delay through 2013, President and CEO Stephen Ubl said.

Democrats' decision to rely on party leaders to hammer out a final proposal, rather than a larger negotiating committee, could also give lobbyists fewer targets to pitch.

It is a very challenging environment, Ubl said.

Generic drugmakers are counting on supportive negotiators such as House Energy and Commerce Committee Chairman Henry Waxman to roll back brandname biologic drug protections and add more incentives for the use of cheaper, generic medicines.

We're very hopeful in a small group they have a chance to pull out some very sound policy, Generic Pharmaceutical Association President Kathleen Jaeger said.

Another hurdle is pressure on Democrats during an election year to band together and pass a bill before President Barack Obama's State of the Union address in early February. The House reconvenes Tuesday, while the Senate returns to work January 20.

Healthcare companies are trying to reduce and delay parts of the bill, said Washington Analysis Corp healthcare analyst Beth Mantz Steindecker, but it's not about the insurers anymore -- it's about the different Democrats.

FINE-TUNING

The desire to wrap up the process quickly should favor biotechnology companies and pharmaceutical manufacturers, which have scored major victories so far.

Biotech companies such as Amgen Inc and Genzyme won 12-years of exclusive sales before their expensive, protein-based medicines would face generics. Pfizer Inc, Merck & Co Inc and other drugmakers secured an early deal with Senate Democrats and White House.

Frankly, we're pretty much looking to preserve what we've already accomplished, said James Greenwood, president and CEO of Biotechnology Industry Organization (BIO).

Greenwood said his group will not introduce any new elements into the process but will press lawmakers for fine-tuning. In particular, BIO wants to curb an expansion of a drug discount program known as 340B that it says should be contracted and limited to uninsured patients.

A small negotiating group could even help. The good news is you have to talk to fewer people to get your message across, Greenwood said.

The Pharmaceutical Research and Manufacturers of America (PhRMA) is spending millions to protect its deal, that includes thwarting bids to import cheaper drugs from other nations. Its members have agreed to pay $2.3 billion in taxes over 10 years and help close a gap in the Medicare drug program for seniors.

It made no such deal with House Democrats, whose bill seeks more rebates. They also eliminated the Medicare drug coverage gap known as the doughnut hole. Senate Democrats back that idea but have not said how they would fund it.

Drugmakers -- a $315 billion industry with a powerful Washington lobby -- have publicly made clear they will not budge, citing the House bill's chilling effect on the industry.

We believe the Senate bill provides the best blueprint for real reform, said PhRMA Senior Vice President Ken Johnson.