A Chinese businessman who disguised $20,000 cash in a gift box of breakfast tea in a bid to speed up his solar company’s applications before Australia’s Clean Energy Council was heard saying he knew it was “against the law”.

Guoxin Zhu, 40, who worked for Growatt, a Chinese-based renewable energy company, pleaded guilty in the Brisbane Magistrates Court on Thursday.

The court heard Zhu had organised to meet with an official from the council at a cafe in Camp Hill, in Brisbane’s south, in July when he handed her a gift of tea, which also contained the cash.

The council’s manager reported the offending promptly, the court heard. She is not accused of any wrongdoing.

Zhu was later arrested at Sydney Airport while he was trying to board an international flight.

Prosecutor Bimal Raut said the offending was highly serious.

As the primary body of renewable energy in Australia, the Clean Energy Council managed approvals for solar and battery products, which were also connected to federal government rebates, Raut said.

He said Zhu had organised to meet the manager twice, and openly discussed with her the possibility of expediting his application. She told Zhu she could not accept gifts.

“What is also concerning, then [Zhu] has realised, OK, here, the manager is not going to accept anything directly,” Raut said.

“Then, in a deceptive manner, he says it’s only tea, Chinese tea, it’s a cultural thing.

“What is then shocking to the manager when she opens the box later at home, that’s when she finds the $20,000 cash.”

Raut submitted Zhu, who has been in custody for about a month, should serve a 12 to 15 months’ suspended jail sentence, which would deter future offending.

In a letter from Zhu to the court, the 40-year-old claimed: “When I committed this offence, I had no idea this type of conduct was viewed so seriously by the law. I just did not know it was a serious offence.

“In my country, gifts like this are often given. I did not intend to do anything which was disrespectful to Australia or Australian culture.”

Zhu’s barrister, Saul Holt KC, argued his client was seeking to expedite the process before the council, rather than the approval itself.

“Mr Zhu is viscerally ashamed of the position he finds himself in,” Holt said, detailing the difficulties his client had experienced while in custody away from his family in China.

“The cultural overlay is not an excuse by any stretch of the imagination, but it is relevant in the sense that he’s conducting himself in a way which might be acceptable somewhere else, but isn’t acceptable here,” Holt told magistrate Peter Saggers.

“He understands that, and he apologises without reservation.”

In sentencing Zhu, Saggers said the manager contacted Zhu and told him it could not be done like that in Australia.

Zhu had responded: “Yeah, I know, I know, OK, so I know it’s against the law. I’m sorry, I’m sorry for the trouble I brought to you, I am really sorry.”

Saggers said he accepted Zhu’s claim the bribe was not to get the council’s approval, but to push Growatt’s applications further up the line for consideration.

Zhu, who will leave the country immediately to return to China, received a 12-month suspended sentence after his month in custody.

Outside court, Zhu’s solicitor Mark Williams said his client looked forward to going home to see his family.