About 400 residents living in Werribee and Wyndham Vale will have their properties rezoned to the suburb of Mambourin under a Wyndham council proposal.

The council will submit a proposal to the Office of Geographic Names, to extend the Mambourin boundary east to the Regional Rail Link, so it will begin at Greens Road and extend south to Bulban Road.

Wyndham mayor Cr Mia Shaw said the suburb boundary review was requested by a developer because an estate under development, known as “Mambourin”, would have caused a number of properties to be divided between the suburbs of Mambourin, Wyndham Vale and Werribee, rather than just being contained in the Mambourin area.

Cr Shaw said the realignment would result in about 400 residents in the Cornerstone estate “potentially being in a different suburb to which they originally bought in”.

“This has been a very difficult decision for council and we sympathise with affected residents,” she said.

However, Cr Shaw said emergency services consulted about the proposed change – including fire, ambulance and police – had cited concerns around potential confusion for people when dialling triple-0, if a suburb and estate had the same name but different boundaries.

“It was noted that because of the use of Mambourin as both a suburb name and estate name, a triple-0 caller may not know exactly which suburb they are in and this verifying process could delay the dispatchment of an ambulance or other emergency service,” she said.

“We have a duty to make decisions in the interests of public safety, so this was the main factor in adopting the option recommended by the emergency services.”

Residents who will be living in a different postcode following the realignment will be sent a letter about the decision and options for their next steps, in the coming weeks.

The council sent about 550 letters to residents and ratepayers notifying them of the proposed boundary change.