But current mayor Stephen Bali says while the loss of the Giants was "a bodyblow" for Blacktown, he has urged Canberra to grab the Manuka Oval redevelopment proposal "with both hands".

Mr Pendleton, who still sits on the council, said in the early days of GWS, the team made assurances it was going to maintain a presence in Blacktown for the long-term and was committed to the western Sydney city.

However, within three years, GWS had shifted its senior team's training base from Blacktown 25 kilometres closer to the city, to Sydney Olympic Park at Homebush where it could also play its home games

Mr Pendleton said "the Giants came in and they were going to do this and going to do that and then they got a better offer".

"They came to Blacktown because it suited them.They got a better deal and they left," he said.

Mr Bali, meanwhile, said if the GWS had stayed at Blacktown, he believed the council could have succeeded in redeveloping its current 10,000-seat stadium into an elite-level expanded facility that could accommodate premiership games by partnering with a private consortium.

"We had proposals to use private money to be part of the group consortium to build a stadium which wouldn't have cost the state government one single cent," he said.

"The NSW government is putting almost $2 billion into its stadium policy. You wonder about its priorities. You look around Europe and the US, it's private consortiums that build stadiums, not governments."

Mr Bali said a new stadium would have "reinvigorated" the Blacktown central business district. He urged Canberra to grab the Manuka Oval redevelopment proposal "with both hands".

"I'd say grab the opportunity and go with it because you're getting a business case at the same time GWS is growing in stature and improving on the ladder and capturing the hearts and minds of regional NSW, western Sydney and Canberra," he said. "In five to 10 years, they'll be extremely competitive and a team we can all be proud of."

GWS and developer Grocon have revealed an $800 million proposal for Canberra which would see land around Manuka Oval developed for a hotel, serviced apartments, retail, residential and office space bankrolling an $80-$100 million upgrade of the oval. GWS says it is part of its aim to make Canberra "a genuine home beyond the initial 10-year partnership" with the ACT government which expires in 2021.

Mr Pendleton said the proposal sounded good in principle but he warned Canberra authorities to be sure any contract was ironclad and penalties included if certain assurances were reneged on.

"Based on the experience at Blacktown, if I was involved in another dealings with GWS, I would want to make sure the contracts were very tight and each party had to commit to what they had undertaken in monetary terms and contractual terms. So they can't just say, 'Oh, well, we're going'," he said.

Mr Pendleton said GWS were presented with an offer it couldn't refuse with $11.5 million purpose-built facilities at Sydney Olympic Park.

"Commercially, it was good for them but for Blacktown, I just say they dumped on us," he said.

The NSW government together with the AFL, Cricket NSW and Blacktown City Council funded the development of the AFL/Cricket centre at Blacktown International Sportspark at a cost of $27.5 million, opening in 2009.

The GWS had a presence at Blacktown from 2010 and moved their senior team to Sydney Olympic Path at Homebush in 2014. At least part of the problem was the Giants had to share the Blacktown facilities with Cricket NSW and there was a crunch when GWS' training started in the summer.

GWS chief operating officer Richard Griffiths said the Blacktown facility didn't meet the needs of the team but the Giants still had "deep connections" to Blacktown including basing its academy of young players there.

"There was a funding model there that the Blacktown City Council and the AFL was hoping would come to fruition to be able to build a facility that could accommodate an elite AFL team. That wasn't forthcoming," he said.

"So therefore as an AFL club, we were training out of basically demountables and there was no prospect in the short or medium-term future for us to have an elite facilities to compete with the likes of Collingwood or Adelaide or West Coast Eagles. We needed to find an appropriate facility and we were able to secure that at Sydney Olympic Park.

"We have our academy at Blacktown. We're good partners with the council. We hold our fan days there. We play NEAFL [North East Australian Football League] games there. Development staff are based at Blacktown. It's a very important region to us. We continue to activate out there. But in terms of an elite facility, it wasn't possible that was going to come to fruition."

Only one of the 21 NEAFL games the second-tier Western Sydney University Giants play this season is at Blacktown; eight are at Sydney Olympic Park.

Mr Bali blamed NSW government policy to upgrade stadiums closer to the city rather than supporting new facilities at Blacktown for the loss of the Giants' senior team presence in Blacktown.

"So when the government said, 'Here's Homebush; we're upgrading Homebush', what are the Giants going to do? Of course they wanted a larger stadium; a more permanent facility, so of course they went there," Mr Bali said.

"Yes, we felt abandoned at the time,. But that was four, five season ago. I am a foundation member [of the Giants]. For a few years I was tempted not to be part of it but I struggled through it. And now we're working closely with GWS.

"So the relationship today – as much as you forgive, you don't forget. There's a lot of good partnerships between GWS and the council. We take what we can get."