The approval rating for Prime Minister Shinzo Abe's Cabinet has plunged 10.5 points from May to 44.9 percent, with many unconvinced by the government's denial of allegations of favoritism leveled against Abe in connection with a government project, a Kyodo News poll showed Sunday.

In the nationwide telephone survey conducted Saturday and Sunday, 67.7 percent disapproved of the unorthodox method employed by the ruling parties to force through parliament a contentious "conspiracy" law to punish the planning of serious crimes.

It is the first time since April 2016 for the Cabinet approval rating to stand below 50 percent, although mobile phone numbers were only added to the polling from April this year.

The disapproval rate for Abe's Cabinet stood at 43.1 percent, up 8.8 points. Among those who expressed disapproval, 41.9 percent said the prime minister cannot be trusted.

Among those supporting the Cabinet, 46.1 percent said they could not think of a suitable person to be prime minister apart from Abe.

Regarding the claims that Abe had used his influence in the approval of a new department at a university run by a close friend, 73.8 percent of the respondents said they were not convinced by the government's denial of the allegations.

Only 18.1 percent said they were convinced by the government's explanation regarding the selection of Kake Educational Institution to open a veterinary medicine department in a specially deregulated zone in Ehime Prefecture, western Japan.

Of the respondents, 84.9 percent said the government's internal investigation into the matter did not reveal the facts about the veterinary school construction project, while 9.3 percent said it did.

The ruling coalition of the Liberal Democratic Party and the Komeito party took the unorthodox step last week of bypassing an upper house committee vote prior to holding a Diet vote on the conspiracy bill.

The choice to circumvent the normal legislative process effectively allowed the coalition to avoid extending the Diet session that ended Sunday, sparking criticism among opposition parties that the government was seeking to evade a thorough examination of the contentious law as well as Abe's involvement in the veterinary school construction project.

On Friday, Kozo Yamamoto, minister in charge of the Cabinet Office, which oversees specially deregulated zones, said an internal investigation had found staff did not specifically mention the prime minister's wishes with regard to the project, contradicting files found at the education ministry.

The documents found at the education ministry indicated that officials of the Cabinet Office conveyed the wishes of the prime minister's office in relation to the veterinary school project, employing phrases such as "what the highest level of the prime minister's office has said" and "in line with the prime minister's wishes."

Regarding the conspiracy law, the government argued it would help to thwart terrorism as Tokyo prepares to host the 2020 Olympics and Paralympics, and was necessary to allow Japan to ratify the 2000 U.N. Convention against Transnational Organized Crime.

But opponents, including legal experts, warned it could pave the way to suppression of free speech, invasive state surveillance and arbitrary punishment of civic groups and labor unions.

In the poll, respondents were divided over the conspiracy law itself, with 42.1 percent supporting the legislation and 44.0 percent expressing opposition, while 50.7 percent said the legislation could lead to greater surveillance by the government.

Asked whether the branches of female members of the imperial family should be recognized after they marry commoners, 63.8 percent said they should, while 24.7 percent said they did not see a necessity.

The idea has been proposed to address the decline in the number of imperial family members. The current Imperial House Law stipulates that female imperial members must leave the imperial family when they marry commoners.

As for party affiliation, 34.3 percent said they backed Abe's LDP, down 8.5 points, while support for the main opposition Democratic Party rose 4.3 points to 10.4 percent.

The survey covering 735 randomly selected households with eligible voters as well as 1,052 mobile phone numbers received responses from 504 and 502 people, respectively.