As of April 2021, 90% of NBN fixed-line services could achieve download speeds of 50 Mbps. However, a small number of connections (less than 2%) are not yet capable of normal speeds of 25 Mbps during off-peak times.
In most cases, this is because some NBN lines still must support both NBN technology (such as FTTN) and legacy ADSL technology on the same line. To avoid interference to legacy services, NBN has had to temporarily reduce the power levels used to transmit signals on these copper lines.68
As more ADSL services are phased out over 2021 and 2022, the speed of more lines will improve.