Australia is urging Japan to further lower its tariffs on beef under a Pacific Rim free-trade initiative after Tokyo has agreed to substantially cut them under a two-way free-trade deal struck in April, negotiation sources said Tuesday.

Australia, which became the first major farming country to conclude a free-trade agreement with Japan, is apparently seeking to maintain its competitiveness in the Japanese beef market against the United States, Canberra's rival, which is also involved in the 12-member Trans-Pacific Partnership framework.

Under the bilateral FTA, Japan has already decided to cut its tariffs on Australian beef by up to half the current 38.5 percent. But Tokyo is considering accepting Canberra's demand to accelerate the 12-country TPP negotiations, the sources said.

When the Japan-Australia FTA takes effect as early as the end of 2015, Tokyo will lower its tariffs on frozen Australian beef, mainly used for processed food for restaurants, to 19.5 percent in 18 years, and those on chilled beef, sold in supermarkets, to 23.5 percent in 15 years.

But tariffs will be raised to 38.5 percent when imports exceed certain amounts, so Japan can protect domestic farmers.

Japan is also planning to lower duties on U.S. beef in response to strong calls from Washington in the TPP talks, while Canada also wants to export its beef under the same level of duties as the United States, according to the sources.

The 12 nations involved in the TPP are negotiating tariff issues on a bilateral basis with each country. Agreements to be made under the TPP are expected to take priority over bilateral free-trade deals that have been already struck.