The planned works include metering signals to regulate the traffic flow in order to reduce delays for motorists travelling towards Melbourne.

Macedon MP Joanne Duncan expects the upgrade to be finished by early June.

Ms Duncan said a further $4million would be spent on making Sunbury Road safer. Construction work on the road is expected to continue until September.

The Sunbury Road/Bulla-Diggers Rest Road intersection earned its dubious title last year after the RACV conducted a survey of 6000 road users and rated their worst intersections.

Of respondents who cited the Bulla intersection, 89per cent believed congestion at the intersection was worse than five years ago, and 85per cent thought it would get worse.

Motorists cited traffic congestion and the reduction in the number of lanes along Sunbury Road as the main contributors to the intersection's traffic woes.

RACV chief engineer traffic and transport, Peter Daly, said the survey results were exasperating.

"There is a significant population in Hume and it is one of the most congested areas in Melbourne.

"Fixing things along Sunbury Road will help in the short term.

"What really needs to be done is for Sunbury Road to be duplicated from the Melbourne side of Sunbury to the Tullamarine Freeway, including the roundabout.

"We estimated the duplication will cost about $160 million last year. It has probably gone up since then."