A Saudi woman is to be lashed 300 times and jailed for 18 months for filing complaints against court officials and appearing in court without a male guardian.

Sawsan Salim was convicted last month in a court in Rass, in Qassim province in the north, after petitioning Riyadh officials, including King Abdullah, over what she alleged was years of abuse by local justice officials, the US-based Human Rights Watch said on Wednesday.

Despite her request for intervention, two judges charged her with filing 118 "spurious complaints" against officials, including the judges themselves, and "appearing ... without a male guardian" between 2004 and 2008.

On January 25, she was convicted after a month-long trial before two judges, one of whom was a plaintiff in the case and the original target of Ms Salim's harassment allegations, Human Rights Watch said.

The group has called for higher authorities to quash the verdict.