In a letter to Lesley Titcomb, MP Frank Field asks whether the pensions hole could be plugged by "acquiring assets other than cash" from Sir Philip.
Sir Philip's assets include yachts. He could not be reached for comment.
The regulator launched an enforcement action against Sir Philip after failing to reach a deal with him.
BHS was left with a near-£600m deficit when the department store chain collapsed earlier this year.
There have been reports that the billionaire has offered between £250m and £300m as part of a deal to restructure the collapsed retailer's pension scheme.
However, the Pensions Regulator has so far rejected the offer. The BBC understands that the regulator wants £350m in redress from Sir Philip.
The regulator has sent warning notices of enforcement action to Sir Philip, his retail group and Dominic Chappell - who was the owner when the department store chain collapsed.
The letter released by Mr Field asks for clarification on several points, including whether it is possible to go after the assets held by Sir Philip, his companies, and Mr Chappell.
Mr Field wants to know what powers the regulator has regarding "a person resident overseas or a company registered off-shore".
He asks "whether the regulator can settle a Contribution Notice or Financial Support Direction through acquiring assets other than cash from a person or company from which payment is being sought".
Mr Field later said that no assets were off-limits, including Sir Philip's yachts and property.
The businessman, whose retail empire includes Top Shop, has been strongly criticised by MPs and former BHS staff for taking delivery this year of another super-yacht - reportedly worth £100m - just as the BHS chain was being closed down with loss of 11,000 jobs.
MPs last month backed a call to strip Sir Philip of his knighthood for his role in the collapse of BHS, although that decision would have to be taken by the Honours Forfeiture Committee.
The chairman of a committee probing the collapse of BHS has asked the Pensions Regulator whether assets can be seized from former owner Sir Philip Green.