The average consent time for Ultra-Fast Broadband (UFB) is 37 days.
But the wait is often longer at shared properties or apartments because people face objections from neighbours or get no response at all.
"They could be not consenting because they're not there," Ms Adams said. "They could just refuse to consent because they've fallen out with their neighbours."
Under the law changes, installations on shared properties which cause minimal impact will no longer need consent but neighbours must be given five days' notice.
If an installation will have a lasting impact on a property, neighbours will be provided with details and given 15 days to object, on limited grounds.
If they do not respond, their consent will be "deemed", or automatically given.
"It gives landowners a bit of time to object if there's a problem," Ms Adams said. "But you don't have to chase down an owner who may be a long way overseas."
Apartment owners will also get deemed consent and will be able to install fibre within 15 days if they do not hear back from neighbours.
The minister said the changes were not about "going through people's gardens", but about making it easier for people with shared access to get UFB.
Figures released by Ms Adams showed that UFB installations were well behind orders.
In April alone, 24,000 New Zealanders made an order to get fibre installed. Chorus was able to connect 16,000 homes over the same period.
The law changes will come into force by early 2017 at the earliest.