"We sincerely apologize for the delay and appreciate that eager fans are looking forward to the feature set offered by the two apps," Capcom Unity community liaison Greg Moore wrote on the official site. Capcom says that it is working with Nintendo to roll out the apps as soon as possible.
The Data Transfer Program lets players who own both consoles and both versions of the game to transfer their progress to and from each console.
The Nintendo 3DS Packet Relay Tool allows 3DS versions of the game to play online via a U console. The console requires the Wii LAN Adapter or Wii U Lan Adapter for the relay packet tool to work.
The tool doesn't support multiple 3DS' connected to the one Wii U and the Wii U cannot be used for any other function while it is performing the service. Gamers playing online using the 3DS can't host a game, they must enter a game hosted by a Wii U console.
Last month, Capcom announced that it will issue a patch for the Wii U version to unlock cross-region play between gamers in North America and Europe in April.
Monster Hunter 3 Ultimate launched March 19 in North America and is launching March 22 in Europe on Wii U and Nintendo 3DS. For details about Monster Hunter 3 Ultimate read Polygon's review here.