Prime Minister Yoshiro Mori, who has come under fire a number of times for making controversial remarks, on Tuesday expressed sympathy for a lawmaker facing suspension from the Diet.

"It is not incomprehensible to feel like throwing (water)," Mori told reporters at his official residence, referring to Kenshiro Matsunami, who faces suspension from the Diet for throwing a glass of water at opposition hecklers during a Diet debate Nov. 20.

Opposition heckling is "quite terrible," Mori said. "We should record all the heckling and make it public. I wonder if it is suitable for lawmakers to make (such comments) in the Diet."

But Mori also quipped, "Water in glasses should be drunk, not thrown."

"Did you know that the water at the podium is changed each time (the speaker changes)? Diet staff take care of those things, so it would be a waste to throw it."

Opposition leaders, however, lashed out at Mori's remarks.

Social Democratic Party leader and former Lower House Speaker Takako Doi said Mori disgraced the Diet by making such an irresponsible comment on the Diet decision.

"He is not aware of the significance of the issue or the situation surrounding him. We must grill him on the matter," said Hirotaka Akamatsu, Diet affairs panel chairman for the main opposition Democratic Party of Japan.

The SDP decided to question Mori on the issue during Diet committee sessions.