Can the poem "Goblin Market" be seen as demonstrating a power struggle between men and women?
Absolutely! One can argue that "Goblin Market" is a direct result of Christina Rossetti's opinions on Victorian gender roles and sexual politics.
Within the poem, men take the shape of the evil goblins who destroy women by convincing them to taste their enchanted fruits. Women are the victims of this temptation, becoming sick and eventually dying if they choose to indulge.
The story's heroine, Lizzie, resists the coaxing of the goblins and saves her fallen sister with a kiss. The narrative as a whole seems to walk an interesting line between Christian values (the goblins' fruit serving as a symbol of sex; the death that women experience from eating the fruit as a spiritual or moral death; the Christ-like sacrifice of Lizzie) and intense sexual imagery (the kiss itself, the emphasis on sucking, the fact that the fruit must be eaten in front of the goblin men, etc.). Men seem to pose a true threat to the well-being of women within this context, particularly through their sexual presence and offering of carnal knowledge outside of the boundaries of marriage.
It certainly can. In this poem, the goblin men try to tempt the women to taste their fruit. They woo the women with grand descriptions of that fruit, making it sound as appetizing as possible. However, when women take the fruit, they are left abandoned and ill. It is the women's only salvation to resist the temptation.
Therefore, the struggle is between the ability of the goblin men to seduce the women, and the will power of the women to resist. When they resist, as Lizzie does, they gain power. So much power, in fact, that the hero Lizzie is able to reclaim her sister from the effects of the contaminated fruit. Her integrity and resistance has made her more powerful than the goblin men.