ARTICLE AD BOX
P&O Ferries faces a probe into the controversial no-notice sackings of nearly 800 members of staff.
The Insolvency Service has launched criminal and civil investigations into the circumstances around the redundancies.
In a letter, it said it would consider "prompt and appropriate action" if the law was broken.
Grant Shapps has also asked the service to consider disqualifying its boss from acting as a company director.
The transport secretary made the announcement as part of new pay plans for the ferry industry this week after P&O Ferries sacked 786 employees without notice and replaced with them with agency workers.
He urged ports to block ferries from docking if they do not pay their crew the UK minimum wage, with plans to create new laws.
Mr Shapps said the move would force P&O Ferries to "fundamentally rethink" its decision.
Last week, P&O Ferries' boss Peter Hebblethwaite admitted that the firm knowingly broke the law by not consulting with unions and planning to compensate workers instead.
Ferry industry groups, however, hit out at Mr Shapps' plans, with the UK Major Ports Group saying they should not have to "be the police for the labour practices of ferry companies".
Unions also expressed disappointment that the plans did not go far enough for workers who had already lost their jobs.
P&O Ferries said on Friday that all but one of the sacked employees had taken steps to accept the redundancy offer made by the company.