SINGAPORE, June 30 Reuters The yen weakened past the closely watched 145 per dollar level on Friday, keeping traders wary of potential intervention by Japanese authorities, while the yuan crept higher as hopes for further stimulus from Beijing gathered steam.

The yen bottomed at 145.07 per dollar in early Asia trade, its lowest in over seven months, though pared losses over the course of the trading day and last bought 144.65 per dollar.

It was on track for a quarterly loss of more than 8, its worst in a year, amid the Bank of Japan39;s BOJ ultradovish stance in the face of its hawkish peers globally.

The yen39;s renewed decline has stoked speculation that intervention by Japanese authorities could be imminent, particularly as the level of 145 per dollar first prompted them to shore up the yen in September.

Japan39;s Finance Minister Shunichi Suzuki on Friday warned against excessive yen weakening.

I don39;t think there39;s a huge line in the sand, because if the other major currencies of major trading partners also move in tandem, it doesn39;t make sense for them to intervene, said Saktiandi Supaat, Maybank39;s regional head of foreign exchange research and strategy.

But of course, people will see 145 as the historical level.

Data on Friday showed core inflation in Tokyo perked up in June and remained above the BOJ39;s 2 target for the 13th month.

The same day, official surveys showed China39;s factory activity declined for a third straight month in June and…