A secret deal Chief Minister Michael Gunner signed with Chinese officials in Shenzhen in 2019 was not approved by the Department of Foreign Affairs and Trade as Mr Gunner has claimed, the NT Independent can reveal.

The revelation comes as the Morrison Government requested the Department of Defence review the Darwin Port agreement signed by the previous CLP government with Chinese-owned Landbridge Group in 2015, and follows the Federal Government recently tearing up Victoria’s Belt and Road deal under strengthened foreign relations legislation.

Mr Gunner initially refused to explain the Shenzhen agreement last year, then claimed it was a “sister cities” agreement, later claiming it was a “sister schools” or “education agreement” between the NT Government and the Shenzhen Bureau of Education.

The “Framework for Cooperation” agreement that was finally released publicly in January, after months of mounting pressure, showed the NT Government had obligated itself to “work together to promote closer relations between the Northern Territory and China”, including “language, cultural, and historical knowledge and understanding” and other undisclosed “school partnerships”.

No further details were released, including an explanation, and it remains unclear why Mr Gunner did not publicly announce the deal after signing it in 2019.

Reports have also indicated that Mr Gunner and the Shenzhen Mayor had signed another deal on “future strategic and pragmatic cooperation”.

Mr Gunner has refused to answer questions about the deal posed by the NT Independent, including blocking a Freedom of Information application before the 2020 election, but told a media outlet last month that the Federal Government had approved the Shenzhen arrangement.

“It is a public document which was done in consultation with the Australian Government which effectively created a ‘sister schools’ arrangement,” he told the NT News.

CLP Senator Sam McMahon told the NT Independent that is not true.

“Neither DFAT nor the Foreign Affairs Minister signed off on or approved the Shenzhen deal,” she said.

“Gunner hasn’t been upfront about this and it’s all been a smokescreen. They have not released any details.

“He needs to come clean about this deal. Is it a sister cities agreement, or sister schools or something related to the Belt and Road? Territorians have a right to know.”

While Mr Gunner was not obligated to run the deal past DFAT at the time, it’s understood Foreign Affairs Minister Marise Payne will be reviewing the arrangement and that it could be terminated if found not to be in the national interest.

It remains unclear why he claimed the Federal Government played a role in the agreement.

The NT Independent first reported the deal last June after a source provided photos of Mr Gunner signing the deal, which was not publicly disclosed to Territorians by the government.

Questions have been raised by Labor Party sources and others on the 2019 trade mission to Shenzhen that Mr Gunner may not have been fully informed on what he was signing in China.

The ABC reported in 2018 that the Gunner Government was not aware of bribery allegations against the owner of Shenzhen-based Donghai Airlines before awarding an undisclosed sum of taxpayer money to the airline for direct flights between Darwin and Shenzhen.

In January, Mr Gunner famously said when asked about China that, “if you allow people to buy what they need, then they don’t invade you”.

Mr Gunner has quietly supported China’s Belt and Road Initiative in the past, saying the Port deal was in both China and the NT’s best interests.

Federal Defence Minister Peter Dutton confirmed on Sunday that the Department of Defence is currently investigating whether Chinese-owned Landbridge Group should be forced to forgo ownership of the Darwin Port on national security grounds.