Newcastle and Manchester City are considering legal action against new rules to restrict related-party sponsorship that were approved by the Premier League on Tuesday.

Both clubs voted against a new requirement for all new commercial deals to be submitted to the Premier League Board for approval, and are now looking at other options for blocking rules they consider to be anti-competitive and open to conflicts of interest.

The tighter rules are a direct response to the Saudi-funded takeover of Newcastle in October, when the Premier League also introduced a temporary ban on any new related-party deals, although that has now been lifted.

As a result Newcastle are now free to enter into commercial contracts with Saudi-backed companies, although they will have to demonstrate that their value has not been inflated which could lead to them being reduced by the Premier League.

Under the new system that was supported by the other 18 top-flight clubs all new sponsorship deals will have to be submitted to the Premier League to be approved.

An independent company will decide whether the proposed deal is of fair market value, while the assessor will also have access to a database of all other deals to determine if it is artificially high.

A shirt sponsorship deal or stadium naming rights deal involving Newcastle, for example, would have to be of a similar level to those paid to the likes of Everton, Aston Villa or Leeds United. Newcastle argue this is anti-competitive however, and have the support of City.