In an interview, Larsen said the pair had shown immense promise since joining pre-season from Zimbabwe.
However, they will only know towards the end of this week if they will be offered a contract to stay with the team ahead of the new season.
“They are among 12 players that we have on trial here and I will tell you they have impressed,” Larsen said in Johannesburg.
“The technical team will meet before the end of the week and decide on the players we will bring on board and I cannot say at this stage therefore if we will sign them.”
Larsen, who guided the side to a fifth place finish last season, added they were in the market for two players, a striker and a midfielder. Nyandoro and Semakweri respectively play those positions at their current clubs.
The two TP Mazembe players did themselves huge favours ahead of the technical team’s decision with solid performances this past weekend.
Nyandoro scored two goals as Celtic defeated Pretoria TUKS 3-0 in a friendly match at the LC de Villiers Stadium in Pretoria on Sunday. Earlier, Semakweri scored the only goal of the match as Celtic triumphed over Platinum Stars.
Meanwhile, the Zimbabwean pair faces stiff competition for permanent roles at Celtic from a number of South African players.
Among other players on trial in Bloemfontein are Masibusane Zongo, Phumelele Bhengu, Stanton Lewis and former South Africa international Mosilo Modubi.
Celtic are winding preparations for the 2011/12 Absa Premiership season, which kicks off in early August.
The team plays Mamelodi Sundowns in the quarterfinals of the MTN 8.Post published in: Football