Cost pressures have led Beach Energy and Mitsui & Co to withdraw schedule and capital estimates for the stage two development of the Waitsia gas project.In a release to market this morning ASX-listed Beach said a review was underway by operator Mitsui into the next stage of Waitsia, as cost pressures mount on the project south of Dongara.The review comes months after contractor Webuild took the job following its takeover of Perth engineer Clough.At the time, Beach revealed its share of total capital expenditure for stage two of Waitsia had been revised upward from $350 million to $400 million to a range of $400 million to $450 million.That suggested the overall cost could move from an originally estimated $750 million to somewhere around $850 million. A target was set also for first production by the end of 2023.But today the company said labour conditions since February had prompted its JV partner to review the cost and schedule guidance entirely.“Since [February], the tight labour market in Western Australia in particular has impacted construction progress at the Waitsia gas plant to create a range of uncertainty in outcomes that means Beach no longer considers it prudent or appropriate to maintain its previously targeted schedule and capital estimates,” Beach said in an ASX announcement.“Review of cost and schedule by the Waitsia joint venture operator and Webuild is ongoing to identify and implement opportunities to mitigate impacts on the project and constrain the range of uncertainty.“Beach will provide an update when this review is concluded.”No timeline was given for the review. Beach said the project was “a key element” in its future growth plans.Shares in Beach, which is 30 per cent owned by Kerry Stokes’ Seven Group, fell around 7 per cent this morning after the news was revealed.The Waitsia review is the latest in a challenging period for the Perth Basin project. It follows the voluntary administration of original contractor Clough late last year, and a 10 per cent reduction in Beach’s Perth Basin 2P gas reserves announced in December off the back of a drilling campaign.The Perth Basin has seen a slew of investment activity by some of the state’s biggest business figures so far this year, with Gina Rinehart’s Hancock Prospecting and Chris Ellison’s Mineral Resources taking over Warrego Energy and Norwest Energy respectively.