She said the Local Government Commission, with two new commissioners, would be taking on the issue of sustainable growth and cohesion in the Wellington and Northland communities, among others.
The new commissioners are Sir Wira Gardiner and Leigh Auton, alongside Janie Annear.
Mrs Bennett said one example was regions ending up with a Council-Controlled Organisation (CCO) to handle water or transport.
"It could mean a different business structure or increased responsibilities and accountabilities for regional councils. Some councils may choose to amalgamate."
Mrs Bennett said she had zero interest in imposing unwanted change.
"But let me be clear - there will be change."
Carterton Mayor John Booth, who attended the conference with Masterton Mayor Lyn Patterson and South Wairarapa Mayor Adrienne Staples, said Mrs Bennett's speech matched a lot of what he wanted.
He said the idea of the Local Government Commission working alongside councils was a welcome shift from a "dictatorial" commission.
"We'd be very foolish if we didn't take on board what she said. If we don't make the effort, she'll do it for us."
Mr Booth believes Wairarapa is ready to work with a commission under a "work together" ethos.
"People run around and say, let's amalgamate, it's easy, but the Minister has said: 'Let's look at everything'. We understand things could be better, and we have to take a Wairarapa-wide view.
"We've got a great opportunity to be sensible."
He thinks any changes should target the 2019 local body elections.