An official report shows users on the NBN’s most expensive plans are suffering the biggest dips in speed during the evening.

The latest Measuring Broadband Australia Report, published by the Australian Competition and Consumer Commission (ACCC), includes data on underperforming services – where a connection fails to meet 75 per cent of its advertised speed at least one time in every 20 measurements.

It shows users of the top 100/40Mbps plans are seeing an almost 6Mbps dip in their evening speeds.

Overall, it found more than 10 per cent of Australians are getting speeds far less than those promised in their plan.

The dip starts after 5pm, peak at 9pm, and then return to normal at 11pm.

Out of 260,000 download speed tests completed on 1,212 whiteboxes over November last year, almost 70 per cent of tests hit 90 per cent of maximum plan speeds – a jump of five per cent from the previous report.

However, none hit over 95.6 per cent of maximum plan speeds.

Optus delivered the highest speeds to customers, followed by TPG, Extel, Aussie Broadband, iiNet, Telstra, MyRepublic, and Vocus-owned Dodo and iPrimus.

Download speeds on fibre-to-the-premises (FttP), fibre-to-the-curb (FttC), and hybrid fibre-coaxial (HFC) sat between 90.5 per cent to 91.6 per cent of the promised speeds.

Fibre to the Node (FttN) connections were the worst at just 82 per cent of the promised speed.

“Consumers with underperforming connections are encouraged to get in touch with their RSPs, and ask whether a technician may be able to fix their connection issues,” ACCC chair Rod Sims said.

“Otherwise, they should be able to move to a cheaper plan with top speeds their connection can actually provide.”