A lawsuit has reportedly been filed against Modern Family star Sofia Vergara on behalf of two frozen embryos she created with her ex-fiance Nick Loeb.

The female embryos, which were created in a third round of IVF treatment shortly before the couple split up in 2013, are listed in the lawsuit as "Emma" and "Isabella", the New York Post has reported.

The unusual court filing is the latest in a long-running battle over their custody.

Loeb, 41, originally sued Vergara in California for ownership of the eggs a few months after they split up.

But he apparently dropped the lawsuit on Tuesday after a California judge ruled in favour of the 44-year-old Colombian-American actress, who rose to fame as Gloria Delgado-Pritchett in the hit US comedy.

The Post reported the new legal action has been filed on behalf of the embryos in the traditionally pro-life state of Louisiana, which the newspaper notes may be more open to offer "special legal protections for frozen embryos".

According to a source cited by the Post, the lawsuit lists a third plaintiff, James Charbonnet, as the embryos' "trustee".

The newspaper claims court papers argue the embryos, by virtue of not being born, have been deprived of an inheritance from a trust that was created from them in Louisiana.

It requests the embryos be given to Loeb, giving him the "authority to release them for transfer, continued development, and birth".

The ex-couple reportedly signed a contract at an IVF clinic in Beverly Hills stating neither party could use the embryos without the other's consent.

The new lawsuit alleges this violated California code and Louisiana law, the Post said.

The newspaper's source said court papers accuse Vergara of refusing "to allow her daughters Emma and Isabella to continue their development, so they remain frozen in a tank" in a state of "suspended animation".

The Post report cites Vergara's lawyer as saying the actress wants to keep the embryos "frozen indefinitely".

Vergara married Hollywood actor Joe Manganiello last year. She has a 24-year-old son from a previous relationship.