The plan will allow the two test sites to expand by two test beds each, meaning a total of 16 spots for prototype turbines.
It will also allow for higher tip heights, to test the next generation of offshore wind turbines.
According to Denmark's economy and business affairs ministry, the country's major parties agreed to investigate the possibility of adding to its testing capacity.
Since then, an environmental impact assessment has been completed with input from local stakeholders and residents to the test sites.
"The expansion of test sites is central to maintaining Denmark's global leadership position in the wind area, as well as maintaining the competitiveness of the Danish test centres," said Denmark's energy minister Lars Lilleholt.
"The test centres support the Danish wind turbine industry so that new and more efficient turbines can be developed within the country's borders. It also contributes to reaching the government's goal that Danish energy needs to be covered by at least 50% renewable energy in 2030," he added.
Høvsøre test centre is located in north-west Denmark, roughly 100km north of Esbjerg. According to the site's operator, the Danish Technical University (DTU), it currently comprises five turbines.
The Østerild test site, meanwhile, has seven prototypes in operation, which will be expanded to nine, under the proposals.
It is located in northern Denmark, roughly 70km west of Aalborg.