On its way, the Belgian convoy will pick up assistance provided by Austria (10 water pumps and three power generators).
The assistance is scheduled to arrive in Romania on the evening of Monday (5 July), the European Commission said in a statement.
Offers from Estonia and France are currently still being examined by the Romanian authorities.
Romania has been hit by unprecedented rainfall, resulting in massive flooding in recent weeks. The death toll has risen to 25 and Romania officially asked for help on Friday evening (2 July).
Romania's request for assistance was immediately communicated to all EU countries via the Commission's Monitoring and Information Centre (MIC).
The first to answer were the Belgians, who sent out a team of eight specialists equipped with pumping and filtering stations to assist with the relief effort.
"Once again Europe has witnessed new examples of solidarity when disaster strikes," said Kristalina Georgieva, European commissioner for international cooperation, humanitarian aid and crisis response. "I will use the lessons learnt during recent disasters in Central and Eastern Europe to find ways to improve and reinforce our disaster response capacity in the future," she added.
Hungary and Poland were also hit by floods in May and have benefited from EU countries' assistance in the form of sandbags and pumping equipment.
Joseph Daul, chairman of the centre-right European People's Party (EPP), the largest political group in the European Parliament, said: "The European Union is there for Romania and I sincerely hope that the example of Belgium, which has already sent out an intervention team, will be followed by other member states as the economic cost of this natural disaster will be substantial."
Since its creation in 2001, the EU civil protection mechanism has been activated for forest fires in southern Europe in 2009 as well as worldwide, including following recent earthquakes in Haiti and Chile.
Croatia, Iceland, Liechtenstein and Norway also take part in the mechanism, which pools resources to make available to disaster-stricken areas all over the world.