Construction workers have started cutting down trees on Parramatta Road for roadworks on the M4, angering residents who say they were promised no fig trees would be removed.

At least 20 trees were removed from the northern side of Parramatta Road last week, with several dozen more slated for removal in coming weeks.

They covered an area where the distance between Parramatta Road and the M4 is at its narrowest, between Mons Street and Platform Street in Lidcombe.

Lidcome resident Lynette Giglio said the felling of trees came as a complete surprise, given that the contractor had assured her in January last year that no trees would be removed.

Leighton Contractors community engagement manager Karin Ng emailed in response to Ms Giglio's concerns that the widening of the M4 would mean the demolition of fig trees: "The proposed widening will not require the removal of the fig trees along Parramatta Road. The M4 will be widened by altering the alignment and reducing the median."

But as Ms Giglio waited for her bus on Friday morning, she watched in horror as two gums were demolished, followed later by fig trees.

"They knocked them over and squashed them and that took five minutes to take down two trees that are probably 40 years old," Ms Giglio said.

"I was just gobsmacked.

"We look out at Parramatta Road and the nice green wall of fig trees that hides the motorway and blocks the noise and pollution.

"By Wednesday next week it will be gone."

A Sydney Motorway Corporation spokeswoman said the clearing was connected to the Hill Road westbound off-ramp project and not the widening of the M4.

"Using the motorway reserve for this work will minimise impacts on motorway traffic during construction," she said.

The clearing would extend along a 300-metre stretch of the M4 motorway reserve between Hill Road and Birnie Avenue, and mostly involve the removal of a fast-growing Ficus Hillii species ... she said.

The removal of the trees follows the felling of trees along Alison Road in Randwick in January to make way for the light rail.

Opposition Leader Luke Foley, who met residents on Saturday, has called on the government to stop any further demolition of trees.

"The government has a so-called bypass renewal strategy that promises for the Auburn-Lidcombe area a greening of Parramatta Road," Mr Foley said.

"This is completely counter to that."