According to Sats data, overall standards in maths, reading and writing have declined among Year 6 students in England since the pandemic.
These data show that 59% of students met the expected standard in these areas, a decrease from 65% in 2019.
In 2020 and 2021, the national curriculum tests were canceled.
According to the government, Sats results were expected due to the pandemic and there is still "more work" to catch up.
It expects 90% of primary school children to attain the expected standard in math, reading, and writing by 2030.
To achieve this target, unions called for more investment in schools and teaching personnel.
Sats was taken by a majority of 11-year-olds who were in Year 4. This happened after schools closed to all children in March 2020.
Additional school closures occurred while the pupils were in Year 5. Many students also experienced disruptions due to Covid at Year 6.
Individual subjects' results suggest that reading levels have slightly increased. 74% of students met the expected standard in 2019, up from 73% in 2019.
However, the percentage of students who reach the expected level in other subjects has declined since 2019.
Robin Walker, Minister for School Standards, stated that although this was disappointing, it was to be expected given the effects of the pandemic.
"The government values the efforts of teachers across the country in education recovery and recognizes them. However, it also knows that there is still much to be done."
He said that PS5bn had been allocated to help students catch up and that children who are falling behind in maths and English would receive the appropriate evidence-based targeted support to get back on track.
The government's recovery fund is far below what Sir Kevan Collins (ex-catch-up tsar) and education unions said was needed - approximately PS15bn.
After Randstad, the tutoring provider to the government, was terminated, cash will be used to pay for catch-up tutoring.
According to Renaissance and the Education Policy Institute, the amount of disruption caused by Covid is different across England. The poorest pupils are further behind than those who are better off.
Paul Whiteman, the general secretary of National Association of Head Teachers, cautioned about Sats data for this year because "some families [were] much harder hit than others" due to the pandemic.
He said, "It is important to remember that schools have not only focused on academic success but also on emotional and social recovery."
Geoff Barton is the general secretary of Association of School and College Leaders. He said that the drop in writing and math standards was a reflection of "the immense importance of direct classroom instruction in these subjects - which, of course has been heavily disrupted".
He stated that the government's 2030 targets "require substantial investments in schools and the teaching staff".
He said that it was difficult to imagine how this could be accomplished under the current plans.
