As I posted earlier, they were inside the Prime Minister's Official Residence as the protest was on-going.
Portirland blog, posting the TV Asahi's program video (probably will be taken down shortly by Asahi soon), shows what the response was from each of them.
"Minister, there is a huge demonstration right now outside the Official Residence, against the Ooi Nuke Plant restart..." What do you think?
First, Mr. Yukio Edano, Minister of Economy, Trade and Industry:
(...) No comment.
Then Hosono's car scooted right past the demonstrators:
Here's the video of the 11-minute segment in Asahi's report, while it lasts, if you understand Japanese. Ministers' non-comment and comment are about 5:40 into the video. Extremely brief.