The company behind a new UK nuclear power station says “no formal decision” has been made over its future following a report construction would be halted,
The Nikkei Asian Review reported Hitachi’s board would be likely to decide to suspend all work on the Wylfa Newydd plant on Anglesey next week.
In December, the firm said it would do its utmost to ensure the £20bn nuclear power facility went ahead.
A statement from the Welsh Government described the report as “worrying”.
“This is a major project with significant economic benefits to Wales and rest of the country,” the statement said.
“We will continue to monitor the situation very carefully and press the UK government to do everything it can to help bring this project to Anglesey.”
Shares in the Japanese company jumped 8% after the report.
Speculation has been mounting that Hitachi will scrap the Horizon nuclear power plant project due to potential increases in construction costs.
Anglesey’s Welsh Assembly member Rhun ap Iorwerth said the company appeared to be “closer to a decision on Wylfa not progressing”.
“The signs aren’t looking good,” he told BBC Wales’ Good Morning Wales.
On Friday, the firm said suspension of the project remained an option.
“No formal decision has been made in this regard currently, while Hitachi has been assessing the Horizon project including its potential suspension and related financial impacts in terms of economic rationality as a private company,” it said in a statement.
The UK government had been in formal negotiations with Hitachi over the project since June.
The new nuclear plant would aim to have a generating capacity of 2900 MW by the mid 2020s and have a 60-year operational life.
The original Wylfa nuclear plant near Cemaes closed in 2015 after more than 40 years’ service.