Fires already ripped through dozens of homes in Croatia's tourism-focused south on the weekend and firefighters in Albania battled to get more than a dozen blazes under control on Wednesday.

Government agencies in several parts of the Balkans were expecting temperatures to approach 40 degrees Celsius (104 degrees Fahrenheit) on Thursday.

In Croatia, with areas still recovering from fires that forced evacuations and razed homes over the weekend, the fire authority warned of a high fire danger across the country for Thursday.

"We urge citizens to be extra cautious and to contribute to safety along the coast and inland through responsible behaviour," Chief Fire Commander Slavko Tucakovic said in a statement.

From the capital Zagreb in the north to Dalmatia in the south, several regions would be on the "highest level of warning" on Thursday for health and fire risk, the authority said.

"Let's not allow scenes of raging wildfires to become our daily reality," the authority said.

As Albania wrestled its current crop of forest fires under control, there were already fears the hot and dry conditions could spark fresh blazes.

And Serbia too was facing warnings over extreme heat, with the capital Belgrade climbing to 37C on Wednesday and expected to reach 39C on Thursday.

People in several countries were warned to avoid being outdoors in the hottest parts of the day and work from home if possible.