STOCKHOLM (Reuters) - Sweden's defence budget could reach the target of 2% of GDP in 2028 as the country ramps up spending in the wake of Russia's invasion of Ukraine, the military said on Monday.

       The government said in March it would raise military spending to 2%, but said it was too early to say when the defence budget would reach that level.

       "It is not the case that the strengthening of our defence capabilities will happen first in 2028," the Swedish Armed Forces said in a statement. "Significant increases in capacity will happen every year up to then."

       The military will hand over a detailed investment plan to the government in November.

       Sweden, which is not a member of NATO but with which it cooperates closely, has been ramping up defence spending, particularly since Russia's annexation of Crimea in 2014.

       This year's defence budget is estimated to be around 1.3% of gross domestic product (GDP), up from 0.9% in 2015.

       NATO members pledge to spend 2% of GDP on defence, though not all reach that target.

       Sweden's neighbour Denmark - a NATO member - has vowed to raise spending to 2% of GDP by 2033.

       (Reporting by Simon Johnson; Editing by Mike Harrison)