A spokesman for the Pakistan Cricket Board (PCB) said that a notice had been sent to Waqar over his comments made from New Zealand following their 2-1 Test series win there.
"We have asked him to explain his statement over the captaincy," media manager Nadeem Sarwar said.
Former Test captain Waqar, who guided Pakistan to their first Test series win since 2006 by winning the two-match series in New Zealand on Wednesday, had told Geo Super channel that he was surprised by the board decision.
"I am surprised that the board has delayed announcing the captain. I don't know the reasons for this but personally I think the captain should have been named with the team," Waqar said.
The PCB on Tuesday announced its 15-member World Cup squad but said it would name the captain later although all-rounder Shahid Afridi has been given the responsibility of leading the team in the forthcoming one-day series in New Zealand.
Former Test captains and ex-selectors have criticised the PCB decision to delay announcing the captain, claiming it would lead to internal problems in the team and make players insecure.
Sarwar said that all team officials and players were contracted with the board and had to follow certain policies and regulations.