Differences in internet speed and quality throughout Australia can now be compared, using a new website launched on Thursday.

The communications minister, Malcolm Turnbull, unveiled the site, My Broadband, at a news conference in Sydney.

The site relies on data gathered for NBN Co’s broadband availability and quality report, also released in full on Thursday, which maps internet connectivity throughout the country, so the rollout of the national broadband network can be prioritised in the worst-covered areas.

Turnbull said the report identified 1.6m premises that had either very weak internet coverage or none at all. “They are clearly the ones we want to prioritise,” he said.

He said that by prioritising the rollout, areas with a poor internet connection would be covered two years sooner than projected.

The speeds shown on the site are indicative, based on data the government received from telcos. “You may find the service in your own address is not consistent with this, but this is the closest you can do without testing every single premise in the country,” he said.

The government came under fire in December after revising its pre-election estimates of the troubled project’s cost and timeframe. A strategic review found the rollout would cost $12bn more to complete and take four years longer than promised by the Coalition before the election.

But Turnbull on Thursday defended the project, saying it would deliver 100mbs or close to it, for up to a quarter of the cost of Labor’s plan.

“Most people would see that as a very rational course of action,” he said. “Though, this debate has not been characterised by a great deal of science to date.”