Writing on his blog, Law said from December 8, the Courtyard by Marriott in Sha Tin would provide 500 rooms at HK$650 per night.
The hotel will replace the Silka Tsuen Wan as a quarantine hotel for helpers, with the Silka being used for other quarantine purposes from December 1.
The minister said the government has put more quarantine facilities and quotas in place to bring in more domestic helpers and help ease the acute shortage in the city.
An average of 107 helpers arrived in the city every day in early November, almost quadrupling the figure two months ago.
Law noted a drop in the percentage of helpers found to be infected with Covid who came to Hong Kong in the past two months, but their infection rate remained higher than other arrivals.
He said the government will keep an eye on the trend as well as the pandemic situation in the Philippines and Indonesia, which he described as stabilising, before adjusting the policy on the arrival of helpers.