The Mirror says Muto has agreed a £9.5million transfer to Newcastle.
The Japanese striker was on Tyneside on Friday and agreed personal terms to leave Mainz and become Rafa Benitez's most significant signing of the summer so far.
Muto says he is keen to test himself at a higher level and has set himself a ten goal target in the Premier League.
Benitez is pushing Newcastle to ensure two or three more arrivals before the transfer deadline, including another striker and a full-back. The Spaniard is convinced the club has the resources to afford £16.5m West Brom striker Salomon Rondon.