The administration cast the effort as a way to free up jobs in an economy reeling from the coronavirus.
The ban, while temporary, would amount to major restructuring of legal immigration if made permanent, a goal that had eluded the administration before the pandemic.
Trump imposed a 60-day ban on green cards issued abroad in April, which was set to expire Monday.
The administration is proposing a new way of awarding H-1B visas, the official said, awarding them by highest salary instead of by lottery.
H-1B visas are capped at 85,000 a year for people with highly specialized knowledge and minimum of a bachelors degree, often in science, technology, engineering, teaching and accounting.