Fire engineers are reaching boiling point over what they say is another MBIE mistake.

A variety of buildings from hospitals to high-rises are affected by the changes, brought forward in part because of the Grenfell Tower disaster.

The proposed changes to fire evacuation designs were originally complemented by a five month transition period in May.

Instead, MBIE has decided to scrap the transition period and give fire engineers just eight days to adapt to the new rules

Society of Fire Protection Engineers president Michael James said the decision to fast-track changes is naive.

"They thought this would have no real impact, it was just getting the paperwork in place to match what was happening. The feedback I've heard is that we think it does have an impact on timing, for sure."

A variety of buildings from hospitals to high-rises and stadiums are affected by the changes, and James said it could cause severe delays.

"A lot of the buildings that this applies to are large buildings that could take one or two years in the design process."

Frustrated fire engineers say MBIE's decision to fast-track fire safety rules will have the same result with an unnecessarily different method.

OnFire Consulting's principal fire engineer Debbie Scott said that's ridiculous.

"Giving us eight days notice of this intended change is difficult when there are projects we've been designing for months and years in some cases."

The Grenfell Tower disaster in June saw 70 people die after fire spread up flammable exterior cladding on the public housing tower block in London.