Shaikh Salim al-Ali Al Sabah, who heads the National Guard and is fourth in the country's hierarchy, told the daily al-Qabas newspaper on Monday that some members of the family were exploiting their positions by taking decisions unilaterally.
He proposed setting up a ruling committee that would include himself, Prime Minister Shaikh Sabah al-Ahmad Al Sabah and Shaikh Mubarak Abd Allah al-Ahmad Al Sabah, a prominent elder who is highly regarded.
"It is a dangerous indicator when our traditions are ignored and when senior members of the ruling family are pushed aside and decisions are taken unilaterally," said Shaikh Salim.
Hours later, in an apparent response to the remarks, Kuwait's emir Shaikh Jaber al-Ahmad al-Sabah met with Prime Minister Shaikh Sabah and Parliament Speaker Jassem al-Kharafi, and expressed his confidence in Shaikh Sabah, state agency KUNA reported.
Shaikh Jaber said he was keen on "settling the issues in the
interest of Kuwait's security and stability", KUNA said.
"The current situation is wrong and we cannot keep quiet. From my position of responsibility, it is my duty to warn about this constitutional flaw manifested in not following the procedures specified by the constitution and the law," Shaikh Salim said.
"This situation leads to the belief that the majority of government decisions are unconstitutional, which jeopardises its position among its people... Legislation should pass through the correct constitutional channels," he said.
Kuwait's ruling structure is complicated by the illness of both the emir, Shaikh Jabir al-Ahmad Al Sabah, and the crown prince, both in their late 70s.
Prime Minister Shaikh Sabah al-Ahmad Al Sabah, the emir's half-brother, runs the daily affairs of the small nation which controls one-tenth of global oil reserves.
Kuwait's outspoken parliament and some opposition figures have often called on their ailing, elderly rulers to ease their grip on government, and have also demanded a clear decision on the succession.
Shaikh Salim told the daily that excluding family elders from decision-making was a dangerous break with Kuwait's tradition and had paved the way for corruption.
"The situation now is chaotic and everybody is complaining about the disorder, the nepotism, the corruption and the bribery that is rife in the government," Shaikh Salim added.
Shaikh Salim has in the past hinted at feuds within the Sabah ranks and called for unity. "We should work for the unity of the ruling family, because in its unity and closeness lies Kuwait's unity," he said.