Owners SAIC say 700 MG TFs will be produced by the end of the year
Car production has restarted at the former MG Rover plant in Longbridge, Birmingham.
Shanghai Automotive (SAIC) said it had sold 70% of the orders for its new model, the MG TF LE500.
However, it has been suggested the production is not "full scale" as the engines and bodies are being shipped over from China for hand finishing.
An MG UK spokeswoman said Longbridge did have a "full-on" production line with 180 workers on site.
Eleanor de la Haye, of MG UK, said: "We have 180 workers on site working, not necessarily on that line but on support services as well.
"We are hand building cars. We are producing them in the same way we would expect from any other manufacturing facility."
Former Jaguar chief executive Sir Nick Scheele said this could damage the brand for anyone wanting to buy a "British" car.
He said: "The brand must elicit trust and trustworthiness from potential customers."
The company has 55 dealers across the UK and believes the first cars will be with customers by next month.
MG Rover collapsed in 2005 with the loss of about 6,000 jobs. It was bought by Nanjing Automobile Corporation for £53m but they were taken over by SAIC.
SAIC said it hoped to produce 700 of its sports cars by the end of the year. The model will cost nearly £16,500.
Ms de la Haye said: "We are delighted to have reached this important point and are looking forward to seeing the cars in showrooms shortly."
Birmingham City Council leader Mike Whitby said: "This is truly an historic day for our city and our region and it points towards a much brighter future.
"Combined with Tata's recent collaboration with Jaguar and Land Rover this is bringing the rebirth of our automotive industry one step closer to reality."
Longbridge was opened in 1905 by motoring legend Herbert Austin.
As well as producing cars, it was used as a munitions factory during both world wars and began production of the iconic Mini in 1959.
It also produced the popular Metro and Rover 200 models before the Rover company was bought by BMW in 1994.
BMW subsequently sold the firm to the Phoenix Consortium, under whom it went into administration in 2005.
The ex-chief executive of Jaguar cars has spoken about the MG brand