The agreement is aimed at fostering closer ties and boosting trade in goods and services between member countries.

There have been protests in Japan against the pact, amid fears that it may hurt sectors such as farming.

But Prime Minister Shinzo Abe said that joining the group, which includes the US, is key to reviving Japan's economy.

"Emerging countries in Asia are shifting to an open economy one after another. If Japan alone remains an inward-looking economy, there would be no chance for growth," Mr Abe said.

"This is our last chance. If we miss this opportunity, Japan will be left behind."

The trade pact is expected to lead to big reductions in tariffs on goods and services between member countries, boosting trade between them.And with a combined population of more than 650 million people in the countries involved, many believe the pact, once finalised, will benefit businesses operating in those nations.

In Japan, however, the pact has been a topic of hot political debate.

While the country's big businesses are seen as supporters of joining the pact, the country's farming sector has been voicing its objection to any such move.

The fear is that the country's agricultural sector will be hurt by reduced tariffs on farm products.

However, Mr Abe pledged to address those issues and said that the government would ensure that it safeguarded Japan's interests.

"What we really should fear is doing nothing,'' he said.

"We are standing just at the entrance. I promise you that we will guard our sovereignty as we pursue our national benefit through these negotiations.''

Japan's decision to enter the talks comes at a time when its economy has been struggling to gain momentum.

Its growth has been hurt by a decline in demand for exports from key markets as well as a subdued domestic demand.

Analysts said that a trade pact such as the TPP would open up growth opportunities for Japanese businesses and give them easier access to these markets.

They added that the agreement may also prompt Japan to undertake reforms in key sectors, which are seen by many as vital to reviving its struggling economy.

"The plan of getting Japan moving and growing again, does not only depend on printing more money or on fiscal spending, but really depends on liberalising the economy,'' said Martin Schulz, an economist at Fujitsu Research Institute in Tokyo.

"For that, TPP is a core part because it involves all sectors, from energy, to agriculture, insurances, the car industry as well.

"That would be a big step for Japan,'' Mr Schulz added.

According to Mr Schulz, if Japan, the world's third-largest economy, eventually joins the TPP, the group would account for nearly 40% of total global economic output.

"It would be a very, very big area and it would have a significant impact,'' he said.