There has been growing pressure on the Government to find ways to open the borders to foreign students and tourists.
Tourism is worth about $16 billion to the country, while foreign students contribute to a $5b industry.
Given quarantine would likely require a two-week period of restricted movement, international students have been tipped as a group the Government should focus on getting back into the country.
This month the National Party said it would like to see the borders opened to students, provided they can be screened, tested twice and pay for their own quarantine facilities.
"If it doesn't move quickly, New Zealand is at risk of missing out on international students for the second half of 2020, which will cost the economy hundreds of millions of dollars," Opposition deputy leader Nikki Kaye said when releasing the policy.
As far back as May, Education Minister Chris Hipkins said the Government was looking to enable international students to return to New Zealand if they could be quarantined safely.
"Unlike tourists who are coming here for a short period of time, international students are coming here for a year or more," Hipkins said at the time.
"It's quite possible that we would be able to work with international education providers to manage a period of quarantine at the beginning of, say, a year's worth of study so they can come into New Zealand."
Since those comments were made, New Zealand has caught growing numbers of Covid-19 cases at the border - underlining the risk that the virus could return to the country if appropriate precautions aren't taken.
The comments from Robertson today suggest that the Government will need more time to put measures in place that will ensure safe entry of those coming from abroad.