An MP says he is "pressing hard" for a new breed of trains to be built in Flintshire, with up to 1,000 jobs.
Hitachi has shortlisted Deeside Industrial Park and Newton Aycliffe, County Durham, as potential factory sites for the intercity express trains.
Despite reports Newton Aycliffe in County Durham is the favourite, Alyn and Deeside MP Mark Tami said Deeside should be given "full consideration".
Hitachi heads a consortium hoping ministers approve the £7.5bn contract.
The high-speed trains are designed to be faster, greener, able to carry 21% more passengers and it is hoped production will start in 2013.
A Hitachi Europe spokeswoman said although the Agility Trains consortium was selected in February as the preferred bidder for the Department of Transport's programme, the decision was now subject to the new government's spending review.
She added: "The government is looking at every contract like this to ensure that it represents the best value for money.
"We are still waiting to learn whether this programme will go ahead, but we are looking forward to a positive decision."
The spokeswoman said up to 200 people would be employed in building the factory, with a further 800 involved in manufacturing the trains.
Executives have narrowed the choice of potential sites to Deeside and Newton Aycliffe with a third, unnamed location, as a "reserve".
Mark Tami, MP, said: "I'm pressing hard for Deeside to be selected. It would be extremely welcome.
"I would encourage the company to give full consideration to Deeside and the excellent quality workforce available in this area."
A spokesman for the Welsh Assembly Government said: "We have had contact with Hitachi and we would welcome any decision to invest in Wales."