GM will confirm the deal later today. The news will safeguard around 2100 jobs at the factory, and create hundreds more when a third shift is added to the production line by 2015.
Business secretary Vince Cable said that the deal showed the UK was 'a good business environment for the motor industry'.
It is thought that the Unite union's cooperation in recommending a new deal on pay and conditions was central to GM's decision to bring production of the car to Ellesmere Port. The union deal is said to include a two-year pay freeze.
Unite's general secretary, Len McCluskey said: 'From a position of uncertainty earlier this year, there is now a potential for a future at the plant until 2020 and beyond, and with that 700 new skilled jobs at Ellesmere Port itself, and possibly hundreds more in the supply chain.
'Importantly, this move will also bring component supplier plants back into the UK, a development that strengthens our manufacturing base generally.'
Vauxhall Chairman and Managing Director Duncan Aldred said: 'This is great news for the Ellesmere Port factory. We have been able to develop a responsible labour agreement that secures the plants future. This is assisted by the governments industrial strategy; increasing its focus on the manufacturing sector and creating ideal ground for companies to build up long-term investments.
'With Ellesmere Ports proven build quality and a new agreement that ensures excellent cost competitiveness, this facility will provide additional employment and, as the lead plant for the next-generation Astra, will be one of the cornerstones of our European manufacturing footprint.'
However, the good news for Ellesmere Port could mean the closure of the Opel factory in Bochum, Germany.