Swansea Council's cabinet is being asked to make a £110m commitment to deliver the indoor arena project, in what leader Rob Stewart has described as a "do or die" moment for the city.
The Labour administration has already approved £24m for the Swansea Central phase one scheme, which will transform the LC car park and St David's site the other side of Oystermouth Road.
Next Thursday, cabinet is set to authorise the bulk of the costs - £110.7m - paving the way for the main phase of the work to start.
The large sums and borrowing requirements involved have drawn criticism from some political opponents but Cllr Stewart said his party's regeneration plans had public support and had to be delivered.
"Doing nothing is the worst, most damaging option of all," he said. "This is Swansea's chance to catch up."
Swansea Central phase one comprises the 3,500-capacity arena, and an adjacent coastal park. These developments will sit above a large car park.
A new pedestrian bridge over Oystermouth Road will link this site to a new multi-storey car park and a building containing 15 retail units and 36 flats.
Cllr Stewart said failure to deliver Swansea Central phase one would damage business confidence in the city and threaten private sector schemes like the Skyline gondola proposed for Kilvey Hill.
It is also a precursor to phase two, which covers an area roughly from St Mary’s Church to the St David’s multi-storey car park and proposes a cinema, restaurants, shops, 100-plus apartments and a large public sector office hub.
The council estimates that the city centre is losing out on nearly £160m a year because people prefer shopping and days out in the likes of Cardiff and Llanelli's Parc Trostre.
Too few people live and work in Swansea city centre, said the cabinet report, and Swansea's beach, natural environment and leisure offer had not been maximised.
This, according to Cllr Stewart, can't continue.
"We are now being asked to press the button," he said. "It is a do or die moment."
A video overview of the project from last year:
The report also said investment in the city had been piecemeal to date, or - in the case of large-scale plans by private sector firm Hammerson a decade ago - poleaxed by the financial crisis.
An absence of large-scale public sector intervention now, it said, "would see further rapid decline in the city fabric, depopulation, and continuing falls in productivity, skills leakage, and increases in poverty and worklessness".
Cllr Stewart said he believed Swansea Labour had increased its number of councillors in the 2017 local government election on the back of its city centre regeneration pledge.
"People put us in a position to do a job, and we intend to do it," he said.
The cost of Swansea Central phase one has increased from £120m to £129.7m and now a new estimate of £134.8m - the latter rise partly due to enhanced CCTV provision.
The council will need to borrow £79m to deliver phase one - but Cllr Stewart said interest rates were low and borrowing costs were covered in full for the next six years.
In addition, he said, by March next year the council will have cleared £120m of existing debt since 2012.
The Welsh and UK Governments have pledged to contribute just under £23m to phase one, via the city deal for the region, while Pobl Group is to pay just under £5m for 36 flats. Further grants could be secured.
The cabinet report also said the new arena, car parks and retail units would generate an estimated annual income of £1.7m for the council - and this figure could rise - but maintaining these assets would cost it just under £1m each year.
The target completion date of phase one is summer 2021.
Cllr Stewart said the project would not affect day-to-day council services.
"We are not raiding services to pay back borrowing. We have stuck to our guns on this. We are now being asked to press the button. This is our last chance saloon. We cannot continue to fall behind."
Other schemes underway or planned in the city include a £12m overhaul of The Kingsway, Orchard Street and some surrounding roads.
Once completed, the council will lead a new office project at the former Oceana site on The Kingsway, which will link to Oxford Street.
The authority is also redeveloping the Hafod-Morfa Copperworks site, and wants to overhaul Castle Square.
More recently it unveiled plans to convert the Palace Theatre, High Street, into offices and retail space.
Longer term, the council may redevelop the Civic Centre site and surrounding seafront land.
Meanwhile, the cabinet report about Swansea Central phase one will be scrutinised by a panel of councillors on Monday.
Opposition group leader Councillor Chris Holley said he was concerned about escalating borrowing costs further down the line.
"There is a lot of speculation (in the report)," said the Liberal Democrat leader.
"But what happens if we don't get all those grants?"
