Granville Historical Society secretary June Bullivant said residents were not given enough time to have their say on the proposal to bore two archways through the sides of the 175-year-old bridge.

The proposal, part of a plan to create a continuous walkway along the Parramatta River foreshore, was on public exhibition for two months with submissions officially closing last Tuesday.

Ms Bullivant said many residents didn't know the plans were on display and couldn't make submissions. She said they should not have been released during the holiday period.

"I'm quite upset. I think the whole process was handled at the wrong time of the year and people have not been informed," Ms Bullivant said. "I think there should be an extension of the public submission period."

A Parramatta Council spokesman said the display had already been extended to accommodate the holidays and advertisements were placed online and in print and letters were sent to surrounding property owners.

He said the council would continue to accept submissions despite the close of the formal exhibition period.

"Parramatta Council would however encourage all persons who are interested in making a submission to do so by the middle of March 2012 to enable sufficient time for the assessment of the issues raised in the submissions prior to the matter being reported to council for determination," the spokesman said.

Parramatta and District Historical Society president Trevor Patrick said he was happy with the level of consultation about the plans. He said the proposal was sympathetic to the heritage value of the bridge.

"In principle the society does not agree with alterations to heritage buildings or structures however it is noted that the proposed alterations by the addition of two portals are predicated for amenity and tourism reasons," Mr Patrick said.

He said the portals should be kept away from the bridge archway and panels about the history of the bridge should be installed. The proposal is expected to be voted on in council in April or May.