Glamorgan Cricket Club has secured an additional £1m loan via Cardiff council to meet increased costs in redeveloping its ground to a 17,500-seat venue.
The county borrowed £4.5m to help fund £9.5m work at the Swalec Stadium, which hosted an Ashes Test in 2009.
But extra work was needed, including drainage, and this pushed costs to £11.3m.
In return, the club is offering to repay the whole loan by 2023, five years early.
The original loan was taken out in late 2006 and the council executive approved the extension at a meeting on Thursday night.
The money does not come directly from the council's coffers but from a national loan board.
As well as repaying the loan ahead of schedule, the cricket club said it would also establish a "community benefits" package.
This would include coaching sessions and free tickets for youngsters and support for community events.Council leaders have emphasised how money-spinning test matches can bring money to the wider city economy over the next two decades.
Upgrading the old Sophia Gardens from its original 5,500 capacity enabled the club to host the first Ashes test in July 2009.
Cardiff gained the Ashes honour ahead of the established Old Trafford and Durham's Riverside stadiums.
It has also hosted four one-day internationals and has secured three further tests matches up to 2014 as well as six one-day internationals.
But a one-day international with South Africa in 2008, which was washed out due to rain, brought criticism of the ground's drainage and speed of groundstaff.
'Tangible community benefits'
The rising costs of the redevelopment were due in part to new criteria for test match venues being required by the English Cricket Board.
The club spent £600,000 on a new drainage system and a new hover cover, similar to the equipment used at Lord's, ahead of the prestigious visit of Australia.
Cardiff council said it was estimated up to 18 proposed international cricket matches taking place in Cardiff over the 20 years from 2007-2027 could bring up to £45m into the local economy.
Council leader Rodney Berman said the community benefits package offered by the club would cost the council an estimated £900,000 if it tried to provide them itself.
He said: "Hosting the Ashes test was a great success for Cardiff and gave us a global platform, once again putting us centre stage in the sporting world and we were pleased to be able to help GCCC bring this worldwide event to the Welsh capital.
"It is these community developments that are particularly important to the council, which is why I have personally been clear with GCCC that tangible community benefits need to form a major part of any partnership with sporting organisations within the city."