A tale of two Marmites: market entry when your trademarks belong to someone else

Customs authorities in New Zealand have seized several thousand jars of Marmite originating from the United Kingdom. The consignment of the yeast-derived edible paste, which is produced by Unilever and marketed in the United Kingdom and much of the rest of the world under the name Marmite, allegedly infringes upon the trademarks of New Zealand manufacturer Sanitarium, which produces a similar spread also called Marmite. So what is a brand to do when seeking to expand into jurisdictions where a trademark has already been laid claim to for the same goods and services?