Ekeng, 26, fell to the ground shortly after coming on as a 62nd-minute substitute during a league match against Viitorul Constanta, his club said in a statement on their website.
Media reports said he suffered a suspected heart attack and was pronounced dead in hospital two hours later.
“Dinamo lost tonight, forever, footballer Patrick Claude Ekeng Ekeng,” Dinamo said.
football by arynews
“On behalf of everyone at Dinamo, sincere condolences to the bereaved family. God rest his soul.”
The Cameroon FA also confirmed the news on Twitter, while Ekeng’s former club Cordoba tweeted: “There are no words to express our sorrow for the death of Patrick Ekeng.”
Cameroon midfielder Marc-Vivien Foe also died after collapsing on the pitch, during a Confederations Cup match in 2003 against Colombia in France.
Ekeng had also played for Le Mans in France, as well as Swiss club Lausanne.