
<PAGE>
 
                                                                   EXHIBIT 23.4
   
July 1, 1997     
   
  PaineWebber Incorporated ("PaineWebber") hereby consents to the inclusion in
the Proxy Statement/Prospectus of ONEOK Inc. ("ONEOK") and WAI, Inc. of its
opinion and to the references made to PaineWebber in the "Summary", "The
Transactions: Background and Reasons for the Transactions", "The Transactions:
Recommendation of the ONEOK, Board" and "The Transactions: Opinion of
Financial Advisor" sections of such Proxy Statement/Prospectus. In giving such
consent, we do not thereby concede that we come within the category of persons
whose consent is required under Section 7 of the Securities Act of 1933, as
amended, or the rules and regulations of the Securities and Exchange
Commission promulgated thereunder.     
 
                                          Very truly yours,
 
                                          PAINEWEBBER INCORPORATED
                                                 
                                              /s/ George C. Stephenson     
                                          By _________________________________
                                                 
                                              George C. Stephenson 
                                              Managing Director     
