Premier Gladys Berejiklian says shortages of coronavirus testing kits were affecting NSW but warns that ultimately there will be too many people to test.

"There will be no shortage of masks, there is still a back stock of millions, however it has been stated publicly there are issues around the supply chain of testing equipment," Ms Berejiklian said on Monday morning.

"But we will get to a stage where testing will not be the main issue...but there will come a time when demand is beyond our capacity and we will move into another phase.

"We won't be able to test millions of people who potentially have symptoms and we will need to brace ourselves for that phase."