The announcement came as relations continued to worsen between the Sri Lanka Freedom Party and its main coalition partner UNP.
Sirisena had joined hands with the UNP and formed the government in 2015, defeating former strongman Mahinda Rajapaksa's nearly a decade-long rule.
Wickremesinghe is the main minister in the government managing the country's economy while the finance ministry is also held by a UNP minister.
"During the past three years, I allowed the UNP to manage the economy. Still people are faced with economic hardships. From this year, I will take the economic management under me to grant people an economic relief," Sirisena said while addressing a poll rally in the southwestern region of Kegalle.
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At the last week's Cabinet meeting, an angry Sirisena had walked out of the meeting charging that the UNP parliamentarians have begun criticising him.
Wickremesinghe and several other ministers persuaded Sirisena to return to the meeting.
Sirisena on January 3 said that a commission he appointed to probe alleged irregularities in the sale of two treasury bonds has held former governor of the country's central bank Arjuna Mahendren guilty of leaking sensitive market information.
Making public the findings of the Presidential Bond Commission report on television, he said that the panel has also recommended the prosecution of the country's former finance minister Ravi Karunanayake on bribery charges.