Lined up for the opening was Member for Lake Macquarie Greg Piper representing $3.5 million funding for the project from the NSW Government.

Federal Transport and Infrastructure Minister Anthony Albanese and Minister Assisting the Minister for Climate Change, Federal Member for Charlton Greg Combet, represented the Australian Government's $750,000 contribution.

Also on hand were Bob Thorburn and Gail Ryan from Rathmines Progress Association.

They were two of the principal campaigners who lobbied parliamentarians and canvassed residents to find a solution to the killer junction.

"We are grateful to both Greg Piper and to Greg Combet for their support in getting the funding to build a roundabout but there's many, many people who helped us campaign who would have liked to have been present at the opening," Mr Thorburn said.

"It was all done in such an undignified rush to make it an election stunt that we never had a chance to notify anybody. As a result there were just a handful of residents there; it was simply a media opportunity for the election and through the Lakes Mail I would like to offer my apologies to all of those good people who didn't know the opening was on," Mr Thorburn said.

The family of a man who died at the intersection was among a small group of residents and workers to attend the opening.

Neil Dennett died in May 2007 in a car crash that seriously injured his wife, Patricia.

Her granddaughter Katrina Lofberg said she believed the roundabout would allow her grandmother to move forward with her life.

Locals are sceptical of the slip road which absorbs merging traffic from the roundabout.

They say many drivers appear to be unaware that road rules require drivers merging from a side road to wait until there is a safe gap in the traffic.

"The roundabaout would have worked just as well as a plain $1 million roundabout and we would have had more money to spend on other sections of the road," Mr Thorburn said.