Foreign direct investiment in the United States inceased 11 percent last year, although investment by oil-exporting nations declined, the Commerce Department said yesterday.

The agency said foreign direct investment totaled $34.1 billion at the end of the year, up from $30.8 billion a year earlier. But the income from foreign investments declined $200 million to a total of $2.8 billion.

The Netherlands became more firmly entrenched during the year as the foreign country with the most direct investments in the United States - $7.1 billion. It was followed by the United Kingdom, with $6.3 billion; Canada, $6 billion; and Germany, $2.5 billion. Total Japanese direct investment were $1.7 billion.

The increase in investment in the United States was widespread throughtout the world, with the single exception of the 1v nations that make up the Organization of Petrolem Exporting Countries.

The value of direct OPEC investments at the end of 1977 was $157 million, down 3.7 percent from $163 million in 1976. It was the third consecutive year of decline after OPEC investments hit a peak of $201 million in 1974 in the year after a four-fold increase in world oil prices.