Negotiations on the Trans-Pacific Partnership, a potentially world-changing trade agreement, are close to completion after nearly a decade, people involved in the talks have told CNBC. (Tweet This)

The China Shipping Container Lines CSCL Brisbane container ship departs Terminal 3 of Port Botany in Sydney, Feb. 6, 2015. Ian Waldie | Bloomberg | Getty Images

Negotiators concluded another round of TPP discussions on Sunday in Hawaii, sparking some protests but making "significant progress" on a number of issues, according to William Craft, the deputy assistant secretary of state for trade policy and programs in the State Department's Bureau of Economic and Business Affairs. The negotiations involve 11 other countries—Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore and Vietnam. Significantly, the TPP as it's now envisioned does not include China—though sources told CNBC that's likely to change. Parties to the talks seek to ratify an agreement that goes further than earlier trade pacts in addressing concerns such as the movement of digital information across borders, intellectual property and the globalization of supply chains, according to Scott Miller, senior adviser and Scholl Chair in International Business at the Center for Strategic and International Studies.

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No official timeframe is set on completion of the TPP, but a final agreement could come as early as July, according to Shuaihua Cheng, founder and managing director for the China arm of the nonprofit International Centre for Trade and Sustainable Development. Five to seven sticking points remain, but most issues have been settled at the negotiating table, an Obama administration official who was not authorized to speak for attribution told CNBC. "There are some important things [left in the negotiations], but nothing that could not or should not be solvable by ministers being locked up in a room for three days," the official told CNBC. "We think we are in the end game—we can see the light at the end of the tunnel."

Experts suggested to CNBC that the U.S. is getting much of what it wants so far in negotiations, but there are still some areas of compromise ahead, especially when it comes to ease of access to foreign markets. Regardless, the TPP is likely to face an uphill battle in Congress, where politicians have expressed opposition in part on the grounds that the negotiations have been held amid ultra secrecy. Miller pointed out, however, that the private negotiation coupled with public ratification is the standard process for international agreements.

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The administration is taking an upbeat tone on the TPP, but experts told CNBC that a failure at this stage could seriously damage U.S. interests and credibility in the region.

"The TPP is a really important physical manifestation of our renewed focus on Asia," Craft said, adding that "to get this close and not close the deal would send a strong, and frankly negative, message."

The administration has sought renewal of so-called trade promotion authority (TPA), a power granted by Congress that allows the president to negotiate agreements that the legislative branch can then approve or disapprove, but not alter or filibuster. The last one expired for new agreements before President Barack Obama took office.

Renewal could be crucial for the trade negotiations, Miller said, as other countries may want the reassurance of knowing their hard-fought concessions will not be amended on Capitol Hill. Craft confirmed that the issue of the promotion authority has been raised at the trade talks, but he stressed that its renewal was not absolutely necessary for an agreement to take shape. Still, he said, "would it be desirable, useful, helpful to have it? Yeah, you bet."

'China has no choice—they have to join it.'

China is always a huge factor in any discussion of Asian economics or trade, and that has proven no different for the TPP.

After the U.S. first joined the trade talks, China's politicians and its state-controlled media denounced the measure as an effort at encirclement. But that rhetoric subsided over the past year, and discussions are often now focused on how Beijing can sign up for a subsequent version of the agreement, Cheng said. The U.S. and other partners have publicly stated that they remain open to that possibility. Read More China Must Meet 'High Standards' to Join TPP: US Trade Rep

"We're certainly not doing this as an anti-Chinese thing," Craft said. "We can foresee them joining it." In fact, high-level Chinese delegations regularly ask for updates on the talks and have inquired about what would be necessary to get into the trade pact, according to one administration official. "They seem to be trying to ready themselves to undertake at least some of the reforms that would be required before they could credibly say they wanted to join in the second or third tranche of the TPP," the official said.