NSW Transport and Infrastructure Minister Andrew Constance is increasingly pushing back against federal input into the policy area, declaring that Canberra's plans for Sydney should not detract from the state's aggressive agenda.

"I'm a bit sensitive to Canberra suggesting that they can do it better," said Mr Constance.

"I just think we don't want to duplicate functions of government," he said. "We are happy to work very closely with Canberra, that's what we are doing.

"But I'm very sensitive to the fact that the expertise resides within Transport for NSW, some of our project teams, the private sector here, coupled with Infrastructure NSW. I'd like to see real money from Canberra invested into our projects."

The friction between the two tiers of government emerged after the federal budget, in which Treasurer Scott Morrison committed to establishing a federal team to work on attracting private finance into transport projects.

Describing that policy, federal Assistant Minister for Cities Angus Taylor said Canberra could "no longer be an ATM to the states".

"We must have a greater say in how taxpayer dollars are invested in big infrastructure projects, so that we can secure better outcomes for the community," Mr Taylor said.

These comments, however, aggrieved Mr Constance. Through projects such as inner city light rail, Parramatta light rail, and the metro rail link from Sydney's north west and through the city, Mr Constance is in charge of some of the biggest transport initiatives in the country's history.

"We don't appreciate the comments of Angus Taylor," said Mr Constance.

"We don't want an uncapped line of credit. We need real money, we've got the expertise, as demonstrated in NSW at this time where we've got one of the most ambitious programs in the globe."

One emerging area of difference between the two governments is the planning around a Badgerys Creek airport. The two are working on a study into how an airport rail line would work, but Mr Constance said his government's priority was more metro rail lines across Sydney.

The indications from the federal government are that it is pushing for a rail line to run north-south through Badgerys Creek airport, possibly to join with the Western Line at St Marys.

But this line would only put more pressure on the already overcrowded Western Line, a rail corridor Mr Constance says will soon be unable to carry more passengers.

"By 2031, with the T1 Western Line, you quite literally won't be able to get people on trains in the morning peak," Mr Constance said. "So if you feed into the Western Line airport commuters and any growth along that corridor, you're going to end up in strife," he said.

The state government's long-term solution to the problem of the Western Line is a new metro projects to run between Parramatta and the central city.

Mr Constance announced the West Metro line last year, with an intention for it to be running by the middle of next decade.

"Ultimately we've got to be very careful that whilst Canberra is pushing hard in relation to the best rail option, and we will see the scoping study results in the next few months, that airport line is very much about giving western Sydney commuters a service to the airport and that corridor - but we've got to be very sensitive to the impact on our existing rail network," Mr Constance said.

Mr Taylor said: "The Prime Minister has resolved to bring skills in-house, into his own portfolio, to find better ways to invest and deliver quality infrastructure sooner.

"Australians are not served by a federal government that takes a passive approach to infrastructure investment."