Hungary's government and all parliamentary parties will be represented at the funeral of the Roma man and his small son, who were shot dead after their house was set ablaze, government and party spokesmen said on Monday.

The funeral will take place in Tatarszentgyorgy, C Hungary, the site of the murder, on Tuesday, and police expect thousands of mourners to arrive from all over the country.

The government will be represented by social and labour minister Erika Szucs, the government spokesman said in a statement.

Last Monday, unknown assailants set the house of a Roma family ablaze, and when the 27-year-old father, with his 5-year-old son in his arms ran out of the building, they were shot dead.

The Hungarian National Gypsy Authority (OCO) requested the political parties, local governments and the NGOs to fly a black flag on the day of the funeral to express solidarity and commiseration.