DIYers will get a pre-Christmas present, able to undertake more of their own minor work without red tape.

And homeowners will have more certainty that bigger jobs will be completed satisfactorily, with builders forced to stand by their work.

Red tape is being snipped out of the $5.7 billion house building sector after Building and Construction Minister Maurice Williamson yesterday announced a rule relaxation on minor jobs but tougher new rules on larger, more risky work where builders will have to say what financial back-up or insurance they have.

Changes to exempt many jobs from needing consent should be ready by December "to allow DIY homeowners to do the broader range of exempted work over the Christmas break", the minister said.

Low-risk jobs like porches up to 20sq m, verandas, car ports, some retaining walls, 2.5m fences and internal walls will not even need a building consent under the law reform, he said.

A stand-alone garage will only need to be certified as having been built by a licensed building practitioner.

Simple single-level houses will get faster consent if built with proven methods and products, he said.

But builders and designers will be forced to stand by their jobs, liable to provide warranties and remedies if disputes arise.

Builders will need to say what financial backup or insurance they have if a fight arises, Mr Williamson said.

The Cabinet has agreed to amend the Building Act 2004 so builders got it right the first time, he said.

The president of the Homeowners and Buyers Association, John Gray, accused the Government of a weak Building Act review, saying changes had stopped short of a national building warranty scheme or fidelity fund which he wanted as a backstop for homeowners.

"The building industry needs to give itself an enema," Mr Gray said.

"The focus on potential liability is a sad indictment on an industry that ... is still failing to focus on quality outcomes to give consumers the level of protection they deserve around their most valuable asset and arguably one of the most important elements of our nation's infrastructure," he said.

Mr Gray called for better contracts which homeowners could understand and which were less skewed in favour of builders.

Registered Master Builders president Warwick Quinn welcomed the changes but predicted building costs would not fall.

Exempting minor work from consents and moving towards lower compliance costs were good but the sector would take time to change, he said.

"It will be compulsory to have a building contract for jobs over $20,000 and dispute resolution will have to be written into that," he said.

Builders would be able to produce more work, faster, without having to wait for consents and inspections. But he rejected speculation the changes would lead to more neighbourhood rows and DIYers knocking up their own jobs.

Verandas and car ports must comply with district plans enforced by councils such as height-to-boundary restrictions, setbacks from fence lines, site coverage and maximum bulk and location restrictions, Mr Quinn said.

The Government had laid good foundations and the federation, whose members employ about 15,000 builders and subcontractors, would work closely with it on the details.

Statistics NZ says 12,146 new houses were built in the year to June 2009, rising to 15,750 in the year to this June.

* 20sq m porches (limit now 15sq m)
* Verandas
* Car ports
* Low-risk work
* Stand-alone garages
* Simple houses
* Replacing inside walls
* Fabric sail shades up to 50sq m
* Heat pumps
* Some retaining walls
* 2.5m high fence (limit now 2m)
* Floor linings
* Internal walls

* $20,000-plus work