Campbelltown MP Greg Warren and Campbelltown mayor George Brticevic have backed calls for more state government investment into Campbelltown Sports Stadium.
The NRL is expected to demand a multi-million dollar compensation payment should the Allianz Stadium rebuild not be completed on time.
The Australian Rugby League Commission has expressed that it would like to see that money invested into suburban grounds like Campbelltown, Penrith and Manly.
Campbelltown Sports Stadium will be used significantly more when Macarthur FC Bulls enter the A-League competition later this year.
Mr Warren and Cr Brticevic said the "rapidly expanding region's biggest sporting ground" deserved a state government financial injection.
"This state government is wasting billions of dollars redoing stadiums in the middle of Sydney, while ignoring venues in the 'burbs like Campbelltown and Penrith," Mr Warren said.
"Campbelltown Sports Stadium deserves some long overdue love and attention from those in Macquarie Street.
"It's highly inconvenient getting to ANZ Stadium and Allianz Stadium via public transport from Macarthur - and the decision to remove direct services to Parramatta means the trip to Bankwest Stadium is also complicated and arduous.
"Macarthur is a rapidly expanding region and our stadium should reflect the needs of our ever-expanding community."
Cr Brticevic said investment from the state government in the local stadium would support the region as a whole.
"It makes sense to invest in this stadium to support employment, entertainment and tourism in the Macarthur - the fastest growing region in Australia," he said.
"The stadium has immediate use with NRL matches and the new Macarthur FC A-League team and recently hosted several matches of the Women's Olympic Football Tournament qualifiers featuring the Matildas on its world class pitch."
Construction work started at Allianz Stadium in 2019 and were expected to be complete in early 2022.
However the NRL has been told the rebuild works have been delayed by up to six months.