Thirapat Sereerangsan, the minister to the prime minister's office, said the government could remain in power for a total of one year and five months due to the slow process of drafting a new constitution.
The generals who ousted prime minister Thaksin Shinawatra on September 19 had promised to draft a new constitution within eight months and to hold elections in October 2007.
But Thirapat said the process could take up to five months longer than that, since the assembly charged with drafting the charter has not yet been appointed.
"Considering the process, this government may remain for one year and five months," he told reporters.
In that case, Thailand would not hold elections until early in 2008.
However, Thirapat insisted that the military-appointed Prime Minister Surayud Chulanont, a former army commander, would remain in power only as long as necessary.
The generals say that Thailand needs a new constitution to weed out the corruption that they say marked Thaksin's five years in office.
They have imposed their own constitution until a new one is drafted, but retained tough limits on the media, political parties and protests.
The country is still under martial law, imposed shortly after their take-over.

Copyright AFP (Agence France-Presse), 2006