Mr Groser was not available for interview as talks went overnight Atlanta-time, but was quoted by Reuters as saying the drugs impasse was holding up a deal in dairy products.
Failure to secure a deal would have long-term implications for the US and its trading partners, he said.
"You can see the summit within reach and it's just a question as to whether or not you've got just enough political energy to reach out and do the last little bit."
Stephen Jacobi, executive director of the NZ International Business Forum, said he expected New Zealand to side with Australia over biological drugs.
"These are all big issues [that remain]. It seems to me that there is the momentum underway to get a deal together.
"If it can't be done, then all is not lost. We can go on to the Apec meeting in Manila...I think we are headed for an outcome, what is unknown is whether it will be tomorrow or not."
Labour's health spokeswoman Annette King said caving to US pressure on biological drugs, which can be used to treat cancers, would be the wrong move.
She wanted assurances that the TPP would protect Pharmac - one of Labour's "non-negotiable bottom lines" if it is to support the deal.
The others are ensuring Governments could not be sued for regulating in the public interest and maintaining the right to restrict farm and housing sales to foreigners.
Ms King said monitoring TPP news was "like waiting for a new Pope".
"We have been waiting for the smoke to appear out of the chimney, and what we are getting at the moment is rumour and people who have snippets."
TPP talks began in 2010 but strong public opposition to the deal here centre on concerns about its impact, such as making pharmaceuticals more expensive.
Thousands of people demonstrated in August, many angry that detail of the deal has been kept secret.
If the deal is not done by tomorrow, there will be one last chance, at Apec in the Philippines in November.
