The nationalities of those who died were not immediately disclosed by local authorities.
India's ambassador visited hospitals where workers were being treated for injuries sustained in the fire.
At one hospital, more than 30 Indian citizens were admitted, the embassy wrote on social media, adding that at least 47 workers had received treatment in hospitals.
Several Indian citizens, including from the southern state of Kerala, were reported to have died in the fire, according to a letter written by Kerala chief minister Pinarayi Vijayan to India's foreign minister that was shared with the press.
A government agency for Keralites living outside the state said it had been told by the Indian community in Kuwait that 41 Indians, including 11 from Kerala, had died in the fire.
Reuters could not independently verify the figures.
Visiting the site, Kuwaiti Deputy Prime Minister Sheikh Fahad Yusuf Saud Al-Sabah said "the greed of real estate owners is what leads to these matters".
It was not immediately clear if any violations had taken place at the building or what they were.
The fire mishap in Kuwait City is saddening. My thoughts are with all those who have lost their near and dear ones. I pray that the injured recover at the earliest. The Indian Embassy in Kuwait is closely monitoring the situation and working with the authorities there to assist… — Narendra Modi (@narendramodi) https://t.co/cb7GHN6gmXJune 12, 2024
Low paid, blue collar workers in the Gulf often live in overcrowded accommodation.
Local authorities did not disclose what kind of employment the workers were engaged in, although like in other Gulf states, Kuwait relies heavily upon foreign labour in industries like construction.
An Egyptian who survived the fire and worked as a driver in Kuwait, told local media the fire had started on a lower floor and that those on higher levels were unable to escape.
He said the building had filled with thick smoke.
Emir Sheikh Meshal al-Ahmad al-Sabah ordered an immediate investigation into the cause of the fire and said that any officials found responsible would be held accountable.
The interior ministry, which said the death toll had risen to 49, was investigating, searching the site for victims and working to identify those who had died, state media reported.
The fire in Mangaf, a city along the coast south of the capital Kuwait City, was reported to local authorities at 6am, Major General Eid Rashed Hamad told state television.
It was later contained.
Another senior police commander told state television that many people had died from smoke inhalation, and dozens were rescued.
He said the building housed a large number of workers.
The senior police commander said authorities had warned against housing too many workers in a single accommodation but did not say if regulations had been flouted.
Indian Prime Minister Narendra Modi described news of the fire as saddening in a post on social media platform X.
"My thoughts are with all those who have lost their near and dear ones. I pray that the injured recover at the earliest," he said.
