The Defence Secretary says the Government is seeking assurances that thousands of British troops will not be affected by new anti-LGBTQ+ laws in Brunei.
The Sultan of the south-east Asian country, Hassanal Bolkiah, has made gay sex offences punishable by death by stoning.
The Ministry of Defence (MOD) says personnel will be protected under an agreement that currently stands between the two nations.
Around 2,000 UK servicemen and women are deployed to Brunei, most of whom are Gurkhas.
Personnel are permanently based at British Forces Brunei, which is a resident base.
The UK operates a rolling five-year agreement to operate in the country, with then-Prime Minister David Cameron signing the most recent in 2015.
The Sultan of Brunei has been a regular visitor to the UK and graduated from Sandhurst in 1967.
His son followed suit in 2011, when the Sultan stood in for Her Majesty the Queen during the passing out parade.
The Minister of State for Asia and the Pacific, Mark Field, told the House of Commons: "As many members will be aware, we have a specific responsibility towards British military personnel and their families who are stationed in Brunei, including as part of our long-standing garrison agreement which dates from the coming into existence of Brunei as an independent state in 1962.
"I can assure the House that we have the necessary protections in place with the Government of Brunei."
The MOD says the terms of the five-year contract means all personnel currently based in Brunei will be protected.
Gavin Williamson appears to have echoed that worry, saying that the UK is intervening at the highest levels to ensure service personnel are not affected.
The existing five-year contract is due to be renewed next year.
The Government says it opposes the death penalty in all circumstances and discrimination on the grounds of sexual orientation.
It also says it will continue to encourage Brunei to uphold its international human rights obligations.