CANBERRA, Australia (AP) — A Chinese Australian writer detained in Beijing on suspicion of espionage since January has urged Australia to maintain diplomatic pressure for his release.

Yang Hengjun was formally arrested last week by the Beijing branch of China's National Security Bureau on "suspicion of espionage," China's foreign ministry said on Tuesday.

Yang said in a statement released by a Sydney-based friend on Thursday he was "extremely grateful" to Prime Minister Scott Morrison, Foreign Minister Marise Payne, other Australian lawmakers and diplomats "for their help."

"I implore the prime minister to help me go home as soon as possible," Yang, 54, said in the statement provided to The Associated Press by Feng Chongyi, an academic who was detained in China for two weeks in 2017 while researching human rights lawyers.

Yang was taken into custody upon arriving in southern China's Guangzhou from New York on Jan. 19 with his wife, Yuan Xiaoliang, and his 14-year-old stepdaughter.

Payne has made multiple representations on his behalf to her Chinese counterpart Wangi Yi, and has told China that the blogger and spy novelist should be freed if he is being held for his political opinions. China has urged Australia to respect its legal processes.

Morrison said Australia did not intend to butt out of Yang's case.

"We'll stand up for our citizen and we'll expect him to be treated appropriately and his human rights to be respected," Morrison told Nine Network television on Thursday.

"There's their own justice process that they'll follow in China and that's appropriate. But these suggestions that he's acted as a spy for Australia are absolutely untrue and we'll be protecting and seeking to support our citizen," he added.

Yang said in the statement that was compiled by Australian diplomats during their monthly meetings with him in detention that the Chinese chief investigator told him "Australia is small and won't care about me."

The investigator "said Australia was dependent on China for its trade and economy and Canberra wouldn't help me, let alone rescue me," Yang said in the statement that was distributed to family and friends.

The investigator "said Australia wouldn't help because I am not white. This is nonsense. He was wrong," Yang added.