A cold snap that killed 30 people in Ukraine over the past five days spread Tuesday to swathes of eastern and central Europe with record lows in Bulgaria and heavy snow in Switzerland and parts of Italy.

Emergency services in Ukraine said most of the dead were homeless people who froze to death on the streets, four were found in their homes, and more than 600 people sought medical help for frostbite and hypothermia.

Authorities opened 1,590 shelters to provide food and heat and were planning to set up 150 more as temperatures plunged to minus 28 degrees Celsius (minus 18 degrees Fahrenheit) in some regions.

Police in Poland reported five new deaths on Tuesday, bringing the overall toll for January to 27 as overnight temperatures dipped to minus 30 Celsius.

In Vilnius, the capital of neighbouring Lithuania, one homeless man was found dead Tuesday, bringing the death toll there to eight since Saturday.

In the Czech Republic, a woman was found frozen to death in a garden shed in the capital Prague, police said.

In the Balkans, a 72-year-old man and a 50-year-old woman were found dead of cold in central and southern Serbia respectively, where the temperatures have fallen to minus 33 degrees Celsius, private B92 television reported.

Since Sunday, three people have died in Serbia and one in neighbouring Macedonia.

Meanwhile, two died in Romania, raising the death toll to eight since Thursday, the health ministry said.

Temperatures plunged to minus 29 degrees Celsius in central Romania on Monday night, sending gas consumption to a record high and forcing a huge increase in gas imports, an official said.

"In Bucharest and across the country, consumption has reached a historic high," from 57 million cubic metres per day earlier this month to 69 million on Monday, economy ministry official Claudiu Stafie told a press conference.

Stafie said imports have risen day after day and were expected to stand at 17.5 million cubic metres Tuesday and hit 20 million on Wednesday.

Neighbouring Bulgaria reported record lows and the Danube started to freeze over, threatening shipping.

Eighteen towns, including the capital Sofia, recorded their coldest January 31 since records started 100 years ago, with the mercury dropping as low as minus 29 degrees Celsius in Kneja, in the northeast, according to the national weather service.

In Switzerland, some 10 centimetres (four inches) of snow fell Tuesday morning, hampering flights, and the weather service predicted temperatures would drop to minus 15 Celsius in the ski resorts of Saint-Moritz and Sils-Maria.

The cold wave began enveloping central and northern Italy on Tuesday, as emergency services braced for the most severe week in 27 years and motorways prepared for traffic disruptions.

Travellers were being advised to postpone long journeys as snow began to blanket the Emilia-Romagna, Liguria, Lombardy, Piedmont and Tuscany regions and the motorways agency said heavy trucks would likely be forced to suspend trips.

Schools and universities have been shut in the northwestern port of Genoa and snow ploughs are on alert at the airport of central Bologna, where the local civil protection agency has declared a state of alert until Thursday.