* Japan trade min resigns in blow to new PM Noda

* PM Noda likely to face harsh questioning over his appointment

* Trade min fuss could hamper cooperation with opposition

Japan's Trade Minister Yoshio Hachiro bows at a news conference after submitting his resignation to Japanese Prime Minister Yoshihiko Noda in Tokyo in this photo taken by Kyodo September 10, 2011.[Photo/Agencies]

TOKYO - Japanese Prime Minister Yoshihiko Noda's new government suffered a blow on Saturday after just eight days in office when the trade minister resigned over gaffes on the sensitive topic of radiation from the tsunami-hit Fukushima plant.

The resignation of Trade Minister Yoshio Hachiro, who handles the energy portfolio, will give opposition parties ammunition for attack as Noda strives to end the radiation crisis at the Fukushima plant while tackling a plethora of challenges from rebuilding after the March earthquake and tsunami to curbing huge public debt.

Hachiro submitted his resignation to Noda after reports that he joked with a reporter about radiation from the tsunami-crippled Fukushima nuclear plant, Jiji news agency and other domestic media reported. It was his second remark seen as offensive to victims of the worst nuclear accident in 25 years.

Japanese media said Hachiro had attempted to rub up against a reporter saying "I'll give you radiation" after visiting the Fukushima plant on Thursday.  

Opposition party leaders criticised the remark and said that they would press Noda himself over his responsibility for appointing Hachiro, NHK public TV reported.

Hachiro had already been rebuked by Noda and apologised on Friday for calling the deserted area near the plant a "town of death", a comment seen as offensive to disaster victims.

Noda, who took over as Japan's sixth prime minister in five years after predecessor Naoto Kan resigned, will face harsh questioning over his appointment of Hachiro and other novice ministers in a session of parliament expected to begin next week. Defence Minister Yasuo Ichikawa has already come under attack for calling himself an "amateur" in security matters.

Noda, who won a bruising battle to become head of the ruling Democratic Party of Japan, has emphasized the need to restore fractured party unity in his appointments, raising concerns that he had done so at the expense of expertise.

"There was already great mistrust of his personnel appointments," said independent commentator Atsuo Ito.  

Noda's quick decision to sacrifice Hachiro would probably help dampen public criticism, but a drop in his voter support could make it harder to obtain help from opposition parties to pass bills in the divided parliament, where they control the upper house and can block legislation, Ito added.