Fly-half Spencer, who confirmed his move to Franklin's Gardens on Monday, will join the squad to face Sir Clive Woodward's men following his appearance with Jonah Lomu in Martin Johnson's testimonial match at Twickenham on June 4.
Te Pou said: "We have respect for Carlos' wish to play in the match in London which will also see the return of his friend Jonah to the rugby field.
"I realise that there has been a degree of speculation regarding his departure to play club rugby in England but we all know now of his wishes to support his close friend and mate Jonah.
"Carlos also has great respect for the Maori jersey and he enjoys being part of the environment and wants to contribute," Te Pou added on www.allblacks.com.
Spencer has played nine games for the New Zealand Maori and last played for the team in 2002.
"Carlos is a class player and he has worn the Maori jersey with distinction so we are naturally rapt that he will be available for selection," Te Pou said.