Goulburn Mulwaree Council has joined the push for a high speed rail link through the southern highlands between Canberra and Sydney.

Wingecarribee has also supported the link, as a part of a plan to develop an international airport in Canberra, instead of Wilton, north of Mittagong.

The Federal Government has begun a scoping study for the Wilton proposal after again rejecting the use of the long mooted Badgery's Creek, in Sydney's west.

One of the major decisions facing high speed rail planners is to where to locate the stations between Sydney and Canberra.

Moss Vale and Goulburn have been suggested, but only one may be selected, because of concerns the more stops along the route, the slower the train will be.

Goulburn Mulwaree Councillor GEOFF PETERSON says momentum is building for high speed rail.