Queensland Premier Annastacia Palaszczuk has defended her commitment to the state's north as three powerful cross bench MPs discuss a referendum on secession.

Ms Palaszczuk says Queensland should be bigger, not smaller, as Katter's Australian Party (KAP) MPs Rob Katter and Shane Knuth, along with former Labor MP Rob Pyne, reignite the debate on whether north Queensland should be its own state.

Annastacia Palaszczuk says Queensland should be bigger, not smaller.

The trio is reportedly mobilising against what they see as a lack of infrastructure investment and interest in north Queensland from a Brisbane-centric government.

The premier said there were parts of northern NSW that shared a greater affinity with Queensland.