The Government has announced a $2.5 billion sweetener for councils who now have 6-8 weeks to decide whether they want to give up their pipes and reservoirs to join the Government's massive plan to merge 67 councils' water assets into four regional water entities.

Concerns are mounting that the Government will force councils into the mergers, known as Three Waters reforms, rather than letting each council pick whether it wants in or out, as had previously been the plan.

Three Waters reforms are on shaky ground, with councils and mayors as diverse as Whangarei and Auckland sounding notes of scepticism and outright hostility. Announcing the sweetener, Prime Minister Jacinda Ardern said the Government would spend 6-8 weeks consulting councils and Local Government NZ, before deciding on the way forward.

Government policy is still to let councils opt out if they want to - but Local Government Minister Nanaia Mahuta's line has hardened in recent months as she has refused to rule out forcing councils to give up their water assets for them to be merged into the new water entities.

It comes as a convoy of 50 tractors and utes are set to thunder down Auckland's Queen St tomorrow as thousands of farmers around the country gear up for a "howl of a protest" that will see vehicles parade through urban centres across New Zealand.

Groundswell NZ has organised the protest in 47 towns and cities on Friday.

Pukekohe to Auckland organiser Scott Bright said that 50 tractors would be escorted by police along the Southern Motorway from Drury starting at 9.20am.

The convoy would leave the motorway at Wellesley St, travel down Queen St before going along Beach Rd and rejoining the motorway heading south from Stanley St.

Listen above as Simon Wilson and Tim Wilson discuss the day's news with Andrew Dickens on The Huddle