SEOUL (AFP) - Kim Jong Un was "re-elected" as North Korea's leader on Wednesday, state media said, as parliament opened a session expected to endorse personnel changes after the shock execution of his once-powerful uncle.

Mr Kim was reaffirmed as First Chairman of the powerful National Defence Commission (NDC) by the new parliament, the Korean Central News Agency (KCNA) said.

The rubber-stamp assembly - the first under the leadership of Mr Kim who took over from his father in December 2011 - gathered after North Koreans last month cast ballots in pre-determined elections where all candidates were unopposed.

Upon his re-election, "all the deputies and participants in the session broke into stormy cheers of 'hurrah!', extending the highest glory and warmest congratulations to him," KCNA said.

The result was an "expression of the absolute support and trust of all service personnel and people in him", it said.

Mr Kim also serves as first secretary of the ruling Workers' Party of Korea and supreme commander of the Korean People's Army, but his re-election as head of the top military body confers upon him ultimate power in the heavily militarised state.

On Tuesday, top party leaders met to decide on personnel changes at the head of the regime in the aftermath of the execution of Jang Song Thaek, who was purged last December after being accused of crimes including treason.

The session of the parliament, the Supreme People's Assembly, is being closely watched for glimpses into power shifts within the secretive regime.