Guangzhou Automobile Group, which has joint ventures in China with Toyota and Honda, has said it would delay increasing production capacity for its own brand cars to possibly as late as 2020.

A spokeswoman told Reuters this was due to a stagnating domestic market amid slowing economic growth.

General manager Wu Song at Guangzhou Auto's own-brand subsidiary GAC Motor had told Reuters in April that it was planning to build two factories with an annual capacity of 200,000 vehicles each by 2016 and 2018.

The spokeswoman, however, said the company was now expected to instead expand annual capacity by 400,000 units by 2020 as part of a CNY34bn (US$5.4bn) investment announced by Wu in Beijing on Tuesday and which also includes further R&D for the automaker's Trumpchi line.

The spokeswoman said the delay was aimed at matching capacity with sales volumes.

Reuters noted that GAC Motor joins other automakers including Volkswagen and General Motors that have already started to trim local production in a weak market. Analysts have said overcapacity is worse among domestic automakers than their foreign rivals.

Overall auto sales in China grew a meagre 0.3% year on year from January to September in an economy that is growing at its slowest pace in around 25 years.

The spokeswoman said GAC maintained its annual sales targets of 160,000 vehicles in 2015 and 500,000 vehicles in 2017, adding that a planned expansion of its existing factory in Guangzhou to 350,000 vehicles by next year was still on track.

GAC Motor's parent Guangzhou Auto Group is China's sixth largest automaker.