Prime Minister Shinzo Abe has decided against holding simultaneous elections for both houses of parliament this summer for fear of undermining the strength of the ruling coalition, senior administration officials said Wednesday.

The decision comes as the Abe administration has been facing intense criticism over its refusal to accept a report by experts that raised questions about the credibility of Japan's pension system as well as the use of erroneous geographical data in selecting a candidate site for a U.S.-developed missile defense system.

With Komeito, the coalition partner of Abe's Liberal Democratic Party, also opposed to holding a double election, the prime minister on Wednesday dismissed the possibility of dissolving the House of Representatives during his first parliamentary debate with opposition party leaders in a year. "It is not at all in my mind," he said in response to a question from an opposition party lawmaker.

The regular Diet session is set to end on June 26. The upper house election will likely be held on July 21 after campaigning kicks off on July 4, sources close to the thinking of the ruling coalition said. The current six-year term for half of the upper house members will expire on July 28.

Some ruling party lawmakers are skeptical that the LDP will be able to increase its seats in parliament following the party's strong wins in the 2013 upper house and 2017 lower house elections.

The LDP-Komeito coalition holds over a two-thirds majority in the lower house but is shy of it in the upper house. To achieve the first-ever constitutional revision, the long-held goal of Abe and the LDP, two-thirds majorities in both chambers are required.

Asked about the possibility of dissolving the lower house if a no-confidence motion or a censure motion against the prime minister is submitted to the Diet, Abe apparently left the option open, saying, "We can't predict how things will turn out."

No election needs to be held for the powerful lower house until 2021.