The estimate includes 100 people who went missing when 150 houses were buried under a landslide in the village of Queja near San Cristobal Verapaz in the centre of the country, according to figures given by the army.
Francisco Argeñal, chief meteorologist at the Center for Atmospheric, Oceanographic and Seismic Studies, said as much as 20 centimetres of rain had fallen in just the past two days in some areas.
In Honduras, about 16,000 people have been rescued in the northern Valle Sula region, authorities said.
Eta made landfall as a Category 4 hurricane in Nicaragua on Tuesday with 140 miles per hour winds.
In Chiriquí, the storm caused the greatest damage, destroying homes, roads, bridges and crops, according to the Panamanian government.
As tropical depression Eta returns to the Caribbean, albeit greatly weakened by its pass over Central America, the cyclone leaves devastation in its wake, including hundreds of bodies.More news: Everton game biggest of Solskjaer's career, says Arsenal legend
Two other landslides in Huehuetenango had killed at least 12 more, he said.
South Florida, near Miami, will likely see the worst of the storm.
As of the 7 a.m. advisory from the National Hurricane Center, Eta had 35 miles per hour maximum sustained winds and was headed east northeast at 13 miles per hour.
SURGE: Surge is not expected to be a major issue for Southwest Florida, however, as Eta moves away from us, our winds will turn onshore and bring the potential for minor surge across southern Collier County.
In Panama, the damage was concentrated in the province of Chiriquí, on the border with Costa Rica, where five people - including three children - died in mudslides. The worst side of any tropical system is the east side, but that will be particularly true with Eta, as the thunderstorms are focused on the east side.
Flash flooding and river overflows were also possible across Jamaica, southeast Mexico, the Cayman Islands and western Cuba, NHC added.More news: Alexander Povetkin v Dillian Whyte postponed as Russian has Covid-19
The rains now hammering southern Mexico are the result of a cold front and tropical depression Eta, which has caused an estimated 180 deaths in Central America.
The NWS says to expect a 40 percent chance of rain throughout the weekend, as well as increasingly strong winds through Tuesday.
In Guatemala, which suffered more than 50 deaths from landslides in impoverished areas in the north and northwest of the country, relief authorities alerted the population of more rains.
In Guatemala, some 150 people are believed to have died, the majority in an avalanche, though the toll has not been confirmed, President Alejandro Giammattei said.
Media in Nicaragua also reported two miners had been killed in a mudslide.
However, according to the US National Hurricane Center, the storm is forecast to zigzag across Cuba and the Florida Keys, avoiding landfall on the US mainland and turning westward into the Gulf of Mexico again by next Tuesday.More news: Joe Biden: 'We're going to win this race'