The hotel group, which is owned by the investment arm of Brunei’s Ministry of Finance, has faced boycotts and protests since Sultan Hassanal Bolkiah implemented the first phase of a tough new penal code that includes death by stoning for adultery and homosexuality.
US television station CNBC reported that the group's Beverly Hills Hotel, which has been at the centre of celebrity protests, has lost $1.5m since the boycott began.
Dorchester Collection chief executive Christopher Cowdray told BigHospitality the losses are having an impact on the hotel's 'loyal' staff, as well as suppliers and partners.
BigHospitality was unable to confirm whether there has been a drop in bookings at the group's UK hotels - The Dorchester, 45 Park Lane and the Coworth Park - but celebrity tweets suggest the boycott has been extended to these properties.
UK travel company Cruise.co.uk and Luxury Travel Magazine have also now joined the boycott, removing Dorchester Collection hotels from their websites.
Cruise.co.uk described Brunei's new laws as 'barbaric' and said guests asking to book a Dorchester Collection hotel would be 'politely told why we are unable to fulfill their request and offered a suitable alternative'.
Cruise.co.uk managing director Seamus Conlon said: “Nothing brings people together more than travel. This is one of the core philosophies of our business and something like this is anathema to that principal. As soon as we heard this news there was only ever one course of action we could take."
UK entrepreneur Richard Branson banned all Virgin staff from staying in Dorchester Collection hotels last week, eliciting a furious response from the Dorchester Collection's social media team.
Call for perspective
In a statement released on Monday, Cowdray sought to distance the hotel group from the politics of Brunei, and urged people to place the situation into a ‘broader perspective’, pointing out that European companies ‘across the board’ are funded by foreign investment.
“Most of us are not aware of the investors behind the brands that have become an integral part of our everyday life, from the petrol we put in our cars, to the clothes we wear, to the way we use social media, and to the hotels we frequent. European companies across the board are funded by foreign investment, including Sovereign Wealth Funds," he said.
“Our hotels are managed by Dorchester Collection. We abide by the laws of the countries where we operate. Other countries’ laws do not affect the policies that govern how we run our hotels.
“Our reputation, which has been built on service and integrity, speaks for itself. We do not tolerate any form of discrimination, we never have and we never will. Our policies are far removed from the politics of ownership.”
He added that the group was 'deeply touched' by the support it had received from its loyal guests and long-standing business partners.