RIO DE JANEIRO, June 20 (Reuters) - Shell is "worried" about a strike by employees at Brazil's environmental agency Ibama that has been affecting licensing procedures, the head of the company's local unit said on Thursday.

Cristiano Pinto da Costa told reporters at an event that so far the firm has not been directly affected by the move, but that as a partner of state-run oil firm Petrobras in the Mero oilfield, it is worried about upcoming licenses.

Ibama since January has been slow-walking the issuance of licenses in Brazil as part of an ongoing dispute with the government over wages and work conditions.

Last week, workers at the agency called a strike, which was approved in at least 14 states.

According to oil lobby group IBP, the strike is reducing the nation's oil output by some 80,000 barrels per day. (Reporting by Fabio Teixeira)