The Prime Minister has launched a veiled backhander at Sydney's disastrous light rail, declaring projects need to be built in a "very timely way" that cause as "little disruption possible".

The comments came after New South Wales Premier Gladys Berejiklian declared the State's migration intake needs to be halved, from around 100,000 to 50,000 a year. Ms Berejiklian wants the levels to "return to Howard-era"

Scott Morrison also inferred Ms Berejiklian's comments were ironic, given NSW had requested "more than 5000 additional migrants" in the last planning year.

Scott Morrison said state governments do not have a leave pass when it comes to infrastructure projects. (AAP)

"I'll take it from those comments from Gladys that she would like those now assigned to South Australia or other places and we can do that," Mr Morrison said.

The Prime Minister went on to say that working with state governments on population does not give them a "leave pass" when building major projects.

"The infrastructure has to get built, and it has to be done efficiently and in a very timely way to ensure there is as little disruption as possible, so small businesses don't get impacted by the management of those projects," he said.

The CBD South East Light Rail is running more than 12 months late and has blown out in cost. The NSW Government is currently being sued by Spanish Contractor Acciona for more than $1.1 billion over "misleading and deceptive conduct".

A senior NSW Minister told 9NEWS it was a bit rich of the Federal Government to lecture the state on its building program.

"We are building $87 billion in infrastructure over the next four years, the Feds are building $10 billion in the next ten years," the source said.