* Abe says he should have taken more time to explain the bill
* Poll on broadcaster JNN shows support down nearly 14 pts to 54.6 pct
* Three other media polls show support down to 50 pct or less
Support for Japanese Prime Minister Shinzo Abe slid in opinion polls after his ruling coalition steamrolled through parliament a tough secrecy act that critics fear could muzzle media and allow officials to hide misdeeds.
Shrinking support could push Abe, who took power last year pledging to revive a stagnant economy, to softpedal his security policies until next year's budget is enacted and a sales tax hike from April is safely navigated, some analysts said.
Abe was quick to defend his action, but said he should have taken more time to explain the bill carefully.
"With humility and sincerity, I must take the severe opinion from the public as a reprimand from the people. I now look back and think with regret that I should have spent more time to explain the bill carefully," Abe told reporters on Monday.
"But there have been no rules on designating, releasing, and preserving state secrets. That is where the real problem is."
Support for Abe's government fell 13.9 points to 54.6 percent in a poll by broadcaster JNN, the lowest since he took office, although backing for the main opposition Democratic Party rose just 0.9 point to 6.8 percent and was dwarfed by the 30.3 percent who backed Abe's ruling Liberal Democratic Party.
"Abe's support tends to drop when he shows his 'Abe colour'," said Nihon University professor Tomoaki Iwai. "But he knows that. I think he will focus on the economy for a while."
A survey by news agency Kyodo showed support for Abe's cabinet fell 10.3 points to 47.6 percent, its first drop below 50 percent in a Kyodo poll since Abe began his rare second term.
His first 2006-2007 term ended when he quit after a year marked by a big election loss, deadlock in parliament and ill health.
REVISED OR ABOLISHED
About 82 percent of the respondents to the Kyodo poll, conducted on Sunday and Monday, wanted the secrets act - which some critics have likened to Japan's harsh authoritarian regime before and during World War Two - to be revised or abolished.
"During the parliament deliberations, there were expressions of concern such as 'Secrets will be multiplied endlessly', 'People will be deprived of their right to know', and 'Daily life will be threatened'," Abe said.
"But such things will never, ever happen."
Abe has said the secrecy act is vital to convince allies such as the United States to share intelligence as he sets up a U.S.-style National Security Council to streamline foreign and security policy.
Top government spokesman Yoshihide Suga told reporters the drop was not unexpected. He attributed the decline to public misunderstanding of the law's content and said the government would continue to explain it to gain support.
The upper house of Japan's parliament late on Friday approved the state secrets act, which toughens penalties for leaks and broadens the definition of official secrets, despite protests by thousands of demonstrators near parliament and criticism from a broad swathe of media and intellectuals.
The law provides jails terms of up to 10 years for public servants or others leaking state secrets. Journalists and others in the private sector convicted of encouraging such leaks could get up to 5 years if they use "grossly inappropriate" means to get information.
Top officials will be able to designate special state secrets in four categories - defence, diplomacy, counter-terrorism and counterespionage - that can be kept secret for up to 60 years, and in some cases, longer.
A weekend survey by the Asahi newspaper also showed Abe's support rate falling, by three points, to 46 percent. In another poll by public broadcaster NHK, support for Abe's cabinet dropped 10 points from a month earlier to 50 percent.
Past governments have stretched the limits of Japan's U.S.-drafted pacifist constitution but Abe wants to go further, including by easing a self-imposed ban on exercising the right to collective self-defence, or aiding an ally under attack.