A Government agency has suspended plans for health and safety staff to work in Brunei after its introduction of new laws that make gay sex and adultery punishable by being stoned to death.

The Health and Safety Executive (HSE) said it had called a halt to planned staff secondments to the south east Asian kingdom after unions raised concerns about the ethical and safety implications, according to reports.

Three employees had been due to travel to the country to help its equivalent agency with regulatory work, but it confirmed that all links with the country would be “paused” pending a review.

Internal HSE emails and notices seen by the Guardian revealed that the organisation was seeking staff to work on projects in Brunei as late as Thursday, days after the strict sharia penal code was announced.

Homosexuality was already illegal in the former British protectorate, but it is now a capital offence. The law only applies to Muslims and punishment will also be "witnessed by a group of Muslims".

Human rights groups who have lobbied against "cruel and inhuman punishments" reacted with horror to the decision.

Amnesty International demanded an "immediate halt" to plans for punishments so "heinous" that they allowed for the amputation of children's limbs.