State Government plans to pump 75 gigalitres a year from the Goulburn River to Melbourne face a potential new hurdle after the Commonwealth Government last week flagged a possible broadening of the environmental assessment process for the controversial Sugarloaf Pipeline.

Calls by the Plug the Pipe group for Federal Environment Minister Peter Garrett to take into account the impact of the taking water out of the Goulburn on the Murray Darling Basin and in particular the internationally significant Ramsar Wetlands, such as the Kerang Lakes, Gunbower Forest, Coorong and Lower Lakes, prompted the Department of Environment, Heritage, Water and the Arts to call for comment on whether the scope should be widened.

If it is, the State Government may be forced to back up its claims the Melbourne water could be delivered by savings from the $2bn modernisation of the northern irrigation districts and so would not impact on the basin environment.

Plug the Pipe has referred the minister to a string of recent reports highlighting the dire state of the Murray Darling system, the parlous state of the Goulburn and the record low irrigation losses which undermine savings forecasts.

Spokeswoman Jan Beer said any assessment of a pipe taking water out of one of the main tributaries of the Murray Darling Basin which did not look at the impact on the basin would be incomplete.

"If they are adhering to the Environment Protection and Biodiversity Conservation Act, they have to look at the impact downstream," she said.

"There are a lot of things that they have just not taken into account."

The original referral is largely limited to the impact of the pipe on threatened plant and wildlife species in its path.

Attempts by the pipe Alliance to complete surveys required as part of the assessment process have been stymied by landholders refusal to grant access.

Plug the Pipe claims most of the 40-45 affected landholders between the river and the top of the divide have refused access to the Sugarloaf Pipeline Alliance surveyors.

This week the Alliance, which has hitherto sought voluntary access, took a more aggressive stance, writing to landholders asserting their right of entry under the Water Act.

* Extract from a full report to appear in Stock & Land, Vic, August 14 issue.