Police spokesperson James Kadadzera said on Wednesday that Human Rights Defenders Coalition (HRDC) leader Timothy Mtambo had handed himself to law enforcement agents on Tuesday to answer charges of inciting public disorder.
He said two other activists, MacDonald Sembereka and Gift Trapence, had earlier been picked up by the police on Monday over the same allegations.
"The activists were mobilising the public in major cities of the country to close all state residences which is against the Police Act," Kadadzera told journalists in the capital Lilongwe.
The Act prohibits demonstrations or any gatherings near government buildings without the permission of the police.
The HRDC has announced plans to stage the protests on 25 March during which the activists would block access to all state residences across the country in a move meant to force Mutharika to assent to recent resolutions passed by Parliament.
Parliament passed a bill on electoral reforms amendment which has May 20 as the date for fresh elections.
It also wants the president should fire Malawi Electoral Commission chairperson Jane Ansah and her fellow commissioners for failing to manage last year’s disputed elections.