UPDATE 1-Brazil central govt budget deficit widens more than expected in May

(Adds details on target)

BRASILIA, June 29 (Reuters) - Brazil's central government budget deficit widened much more than expected in May, Treasury data showed on Thursday, raising the risk that the government will miss its budget target this year as a weak economic recovery weighs on tax revenues.

The central government, which includes federal ministries, social security and the central bank, posted a primary budget deficit of 29.371 billion reais ($8.88 billion) last month, compared with expectations for a deficit of 20 billion reais from economists in a Reuters Poll.

The deficit in the 12 months through May reached 167.6 billion reais, equivalent to 2.59 percent of gross domestic product. The official target for 2017 is for a deficit of 139 billion reais.

($1 = 3.3058 reais) (Reporting by Silvio Cascione; Editing by Chizu Nomiyama and Andrew Hay)