They are employed by Reality, part of the GUS retail and business services empire, and are members of Usdaw, the shop workers' union.
Reality has centres in Lancashire, Manchester, Leeds, and Newtown in mid-Wales. It has refused to give guarantees on job security.
The company is investigating links with India - where wages for call centre workers are a fraction of those in the UK - to cope with the growth in home shopping.
The ballot is scheduled to begin next week, with the result declared on September 11.
"The company will no doubt try to reassure our members that there will be no job losses as a result of outsourcing call centre work to India," Val Pughan, an Usdaw officer said.
"Until we get a job security agreement, our members won't believe the company when it says the use of Indian call centres will not be at the expense of their jobs.
"The union has held mass meetings across the north-west over the last few days, and the company should not underestimate the strength of feeling over this issue."
The union claims Reality began secret trials in India in April without consulting officials. "One of our members stumbled across what was happening when there was a query and the trail led back to India," a spokesman said.
The company took a decision "weeks ago" to use Indian call centres, he said.
"We believe this is a financial decision. Wages in India are £4 a day; here they are £4 or £5 an hour. Our members are being asked to stand down and overtime is sometimes no longer available."
A Reality spokeswoman said the Indian trials were designed to cope with the expansion of business.
"Reality wishes to stress there are no plans to close any UK contact centre as a result of the development."
