BRASILIA (Reuters) - More than one-fifth of Brazilian workers are either unemployed, working part time or have given up finding a job, statistics agency IBGE said on Tuesday, reflecting the severity of the country's deepest recession in eight decades.

The IBGE said the so-called labor underutilization rate rose in the third quarter to 22.9 million people, or 21.2 percent of the workforce, from 18 percent a year earlier.

Brazil's two-year-long recession worsened in the third quarter, according to central bank data, despite expectations of a surge in business confidence following the recent ouster of President Dilma Rousseff, who was unpopular with investors.

Brazil's standard unemployment rate, which takes into account only the jobless looking for full-time work, rose to a record high of 11.8 percent in the third quarter, doubling from 2013, according to data issued by the IBGE last month.

The additional data released on Tuesday included the 12 million unemployed, 4.8 million part-time workers searching for work and 6.1 million jobless who gave up looking. No percentage figures were given for either of the last two categories.

The labor underutilization rate is highest in Brazil's poorest regions, topping 30 percent in the northeastern states of Bahia, Piauí, Maranhão and Sergipe. The lowest came in the southern state of Santa Catarina, at 9.7 percent.

By age, young workers have been hit hardest, with a 37.1 percent labor underutilization rate for those between 18 and 24 years old.

Brazil's unemployment rate was at record lows near 6 percent three years ago, after approximately a decade of fast economic growth that helped lift 26 million people out of poverty.

(Reporting by Silvio Cascione; Editing by Guillermo Parra-Bernal and W Simon)