Three non-ruling parties requested King Norodom Sihamoni to intervene in the final election decision, claiming as many as a million people were denied their right to vote in Sunday's election.
The Sam Rainsy, Human Rights and Norodom Ranariddh parties, each of which won seats Sunday but are contesting the results, wrote a letter to the king dated July 30.
Funcinpec, which had joined the three parties in protesting the elections earlier this week, did not sign the letter. Cambodian People's Party officials say they have made overtures for Funcipec to join with them, after the ruling party claimed to have won 90 of 123 National Assembly seats.
A Royal Palace official said Thursday the palace had not yet received the letter.
"The king has the right to protect and guarantee the rights and freedoms of the general public, especially voting rights," Sam Rainsy said Thursday. "I hope the king will fulfill this duty in conformity with the constitution."
The three parties specifically complained over the way the National Election Committee conducted the election Sunday.
NEC Secretary-General Tep Nitha said the election body was prepared to clarify any of its procedures with the Constitutional Council, which has oversight.
The parties pointed out irregularities from the election.
People with enough documents to vote found someone had voted in their names when they reached the polls, the parties said. Others went to register with an information card, but they could not find their names on voter registries. Still others had their names omitted from voter registries without reason, the parties said.
Funcinpec President Keo Puth Reaksmey said Thursday the party had no plan to further complain over election irregularities.
"Funcinpec is still a partner with the CPP, and we cannot do anything wrong from this partnership principle, so we will not continue to join demonstrations or complaints against the election results or any irregularities," he said.