The United States, the main foreign benefactor of Egypt's military rulers, had suggested that the trial of the activists could imperil that aid.
Several of the American suspects sought refuge in their embassy in Cairo, including Sam LaHood, son of US Secretary of Transportation Ray LaHood and head of the Egyptian chapter of the International Republican Institute.
Negad El-Borai, who represents some of the American defendants, said earlier he did not expect them to appear in court on Sunday.
The other defendants are Egyptians, Germans, Palestinians, Norwegians and Serbs.
"I don't expect them to come, given the way things are going," he told AFP. None of the Americans have been arrested, but they and the other suspects are banned from leaving the country.
The other foreign non-governmental organisations targeted are the National Democratic Institute, the International Centre for Journalists and Freedom House, all from the United States, and the German Konrad-Adenauer Foundation.
Some of the groups had helped train activists and political candidates to campaign in parliamentary elections that began last November, Egypt's freest vote in decades.
The charges, which US legislators have derided as political, came as the military faced growing dissent from activists who demand the ruling generals immediately cede power to a civilian government.
In response, the generals have accused their opponents of seeking to destabilise Egypt, which was rocked by an 18-day uprising last year that overthrew the dictator Mubarak.
Authorities have played on abundant suspicion in the country of foreign plots, seizing on the case as an example of intervention in the Arab world's most populous country.
On Saturday, the government's flagship newspaper said the investigation into the "dangerous case" had revealed "a plan to divide Egypt found in the headquarters of one of the groups belonging to America."
Prosecutors, backed by police, raided the groups' offices in December, confiscating their equipment and sealing their doors.
Borai said he believed the trial was a result of strained ties between Egypt and Washington. "There is a crisis in US and Egypt relations, and the other defendants were all caught in the middle," he said.
Fayza Abul Naga, a Mubarak-era minister who has carved for herself a powerful role in the military appointed cabinet, is widely believed to have instigated the probe in the groups' funding last summer.
She had told investigating judges that Washington funded the groups to cause "chaos" in Egypt.
"The United States and Israel could not create a state of chaos and work to maintain it in Egypt directly, so they used direct funding to organisations, especially American, as a means of implementing these goals," she said in her testimony.
In a visit last week to Cairo, Republican Senator John McCain said he was told by the military ruler Field Marshal Hussein Tantawi that he was working "diligently" to resolve the issue.
But political intervention in the case would belie the authorities' claim they do not meddle with the independent judiciary, which already is facing one of its greatest tests in a murder and corruption trial of Mubarak.