BRUSSELS--Portugal's headline budget deficit could reach 7.5% of gross domestic product in 2014 due to a series of one-off factors, the European Commission said in a report Tuesday.

The commission said that while Portugal remains broadly on track with its agreed fiscal targets for coming years, the budget gap will be higher this year because of costs of the government's debt management program for firms with legacy debts and because of the costs of the Banco Espírito Santo rescue.

The commission said that no further impact is expected from these one-off costs in 2015.

"Specific one-off operations, some of which are still subject to statistical analysis, could push up the headline deficit figure in 2014," said the report.

Stripped of these one-off costs, the commission said Portugal would meet the 4% deficit goal in its 2011-14 bailout program and would run a primary surplus this year of 0.4% of GDP this year--the first since the economic crisis started.

The report shows the government's gross-debt ratio peaking this year at 131.3% of gross domestic product, up from 128.9% last year.

Write to Laurence Norman at laurence.norman@wsj.com

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