"I don't think we're looking at a breakthrough in the near term," Schwab told AFP on the sidelines of the World Economic Forum in the Swiss resport of Davos.
"But I think we're making some progress and some of the key players really are engaging -- Brazil, the EU, the United States and other countries -- and that makes me cautiously optimistic that we are laying the groundwork for a breakthrough," she added.
Ministers from about 30 key trading nations are due to meet World Trade Organisation Director General Pascal Lamy in Davos on Saturday.
Lamy suspended the five-year old negotiations between the WTO's then 149 members on reducing barriers to trade in agriculture, industrial goods and services last July because of the deadlock.
However, diplomats at WTO headquarters in Geneva were allowed in November to resume contacts over technical details of a long delayed trade deal, and negotiators from major players have met each other repeatedly since then.
A senior EU official close to