Atp Oil & Gas (ATPGQ) 10-K/A 2009 FY Annual report (amended)

Exhibit 23.3

CONSENT OF INDEPENDENT PETROLEUM ENGINEERS

We hereby consent to the use of our report, dated February 15, 2010, relating to the proved oil and gas reserves of ATP Oil & Gas Corporation as of December 31, 2009, to the information derived from such report and to the reference to this firm as an expert in the annual report on Form 10-K. We also consent to the incorporation by reference of such reports in the Registration Statements of ATP on Form S-3 (333-162574) and Form S-8 (333-60762).

Collarini Associates

/s/ Mitch Reece, P.E.

President

December 10, 2010