Official campaigning kicked off in Japan on Tuesday ahead of a December 14 national poll that Prime Minister Shinzo Abe has described as a referendum on his faltering "Abenomics" growth blitz.

More than 1,180 candidates nationwide were vying for 475 legislative seats in the powerful lower house of parliament, with Abe's Liberal Democratic Party seen as likely to cruise to a comfortable majority.

The 60-year-old premier still has two years left in his mandate, but he called for the vote in the wake of his decision last month to delay a planned sales tax hike to 10 percent next year.

The move followed a levy rise in April -- from 5 percent to 8 percent -- that slammed the brakes on growth and pushed the country into recession during the July-September quarter.

The tax hike, which was aimed at tackling Japan's eye-watering national debt and huge public welfare costs, dealt a serious blow to Abe's plan to conquer years of growth-sapping deflation.

While his once soaring popularity has taken a hit, there is little in the way of formidable opposition, and observers said his election call was likely aimed at fending off rivals ahead of local elections and a party leadership vote next year.

However, in the wake of several high-profile cabinet minister spending scandals and facing big opposition to Abe's plan to restart nuclear power, the ruling party may lose some of the 295 seats it held before the 480-seat parliament was dissolved in November 21.

Critics have derided the vote -- which will cost taxpayers about $500 million -- as "an election without cause", but Abe has insisted the poll was necessary as a referendum on his controversial big-spending, easy-money policies.

"Employment is improving. Wages are rising. We have come to the point where we can emerge out of deflation," Abe said in a televised debate, hosted Monday by the National Press Club, where he was seen as easily fending off criticism from a fragmented opposition.

"This is the only way. I am moving forward," he added.

Likely majority

The prime minister's pro-business policy blitz, launched in late 2012, has boosted the Japanese stock market and driven down the yen, cheering investors and exporters.

But critics say the programme has inflated inequality, creating new jobs with low wages and limited benefits, while adding to Japan's debt -- already one of the heaviest burdens among wealthy nations at more than twice the size of the economy.

For voters, the state of the economy, streamlining the size of Japan's parliament, and beefed up child care programmes to lure more women into the workforce were the top three issues, according to a survey published by the Asahi newspaper on Monday.

The survey showed that Abe's cabinet maintained an approval rating of 40 percent, nearly flat from 39 percent seen in the same survey taken a week ago.

Some 34 percent of surveyed voters said they would vote for the LDP, followed by 13 percent for the main opposition Democratic Party of Japan.

The opposition has attempted to criticise the conservative leader for his decision to expand the role of the Japanese military, as well as efforts to restart nuclear power after the Fukushima crisis and his visit to the controversial Yasukuni war shrine late last year.