A proposal by Prime Minister Junichiro Koizumi that the country's three public pensions be integrated into one is idealistic, a key aide to the prime minister said Sunday.

"It is an idealistic theory, but the reality is not that easy," Hidenao Nakagawa, the Liberal Democratic Party's Diet affairs chief, said on an NHK TV talk show.

"We must grapple with (pension reforms) together with medical and elderly nursing-care insurance reforms through discussions spanning two to three years," Nakagawa said.

He took issue with Koizumi's remarks Saturday in support of integrating the three public pensions covering salaries workers, self-employed people and public servants. He said he is willing to discuss the issue with the Democratic Party of Japan for about a year.