The Olympic team, who paraded the likes of goalkeeper Emmanuel Daniel, Segun Oduduwa, Sincere Seth, Daniel Etor and Stanley Dimgba, lost 2-1 to the U20s.
“This is what I have been saying – that I don’t have a team because most of the players are being held back by their league clubs,” said Siasia.
“I had only about three regular players in this game and overall we were poor.
“We need to do more before our trip to Korea for the invitational tournament.
The U23 African champions are preparing for the Rio Olympics in August.
They are drawn with Japan, Sweden and Colombia.