Ynetnews.com said Israeli Forum for the Promotion of Equal Share in the Burden is urging Fox to incorporate joining the army or volunteering in Israel's National Service into the 23-year-old supermodel's contract.

Fox last week announced Refaeli -- who is Hollywood actor Leonardo DiCaprio's girlfriend -- would star in the company's campaign for the next three years and would earn about $300,000 a year.

However, Ynetnews.com said critics of the model's decision not to serve in the Israeli military are threatening to boycott Fox if it doesn't drop her or pressure her to join the army or volunteer in the National Service.

"We are not trying to make her life miserable," Reuven Agassi, a member of the forum, told Ynetnews.com. "But celebrities are the country's store-front window and when they express negativity towards enlisting in the army, it has its effect. I lecture at schools and students say, 'Look at that singer or model who didn't enlist and still succeeded.' Our appeal to Fox says that we can't provide economic benefits to people who have not served our country."