Kuwait's public prosecutor wants an appeals court to increase a sentence handed down to three royals for insulting the authorities from five years to 29, according to remarks published Monday.
Dherar al-Asoussi said he had petitioned the court also to convict the men of using social media to insult the Gulf state's ruler.
A lower court last month sentenced the three royals, including a nephew of the emir, and two others to five years in jail for insulting top judges online.
It also sentenced a sixth man to one year and another to 10 years in absentia. Six more were acquitted.
All were acquitted of a charge of insulting the emir.
Asoussi told Al-Qabas newspaper he has challenged the rulings and demanded that all 13 defendants be given harsher jail terms of up to 29 years each for insulting the emir, judges and spreading false news about Kuwait.
The appeals court has not yet set a date for the hearing. Its rulings must be verified by the supreme court.
The royals given jail terms include Sheikh Athbi al-Fahad Al-Sabah, the emir's nephew and a former head of the secret service police.
He is also the younger brother of international sports figure Sheikh Ahmad al-Fahad Al-Sabah, the president of the Olympic Council of Asia and a member of the International Olympic Committee.
The convicted men remain free but the interior ministry said on Monday security forces raided Sheikh Athbi's house but he was not there.
A statement posted on the ministry website said they had wanted to arrest him to serve his jail term.
It said security men found an automatic rifle and a gun and some ammunition which were confiscated, but it did not say if police had tried to arrest the others.
All 13 were charged with using WhatsApp and Twitter to insult the judges and publish false news accusing them of accepting bribes.
Also convicted was Sheikh Khalifa Ali Al-Sabah, the editor of Al-Watan newspaper and television which were closed by the government for violating corporate finance rules in a decision ratified by the courts.