Marketing understands the utilities giant is likely to make more than 40 redundancies from its 231-strong commercial unit, which includes marketing and sales positions.
Those affected within marketing and sales are entering a 30-day consultation period that will conclude early to mid-December.
A British Gas spokeswoman said: "We need to make sure we are running as efficiently as possible given the current climate that we face, as wholesale costs are changing."
The marketing job cuts are part of the planned 850 job reductions announced by Centrica today (Wednesday), as it looks to offset costs.
Will Orr, marketing director at British Gas, said: "The changes we’re proposing are part of our efforts to keep costs as low as possible for our customers, who we know are struggling with stretched household budgets. This is a difficult time for the team, but together we’ll continue to produce demonstrably effective, industry-leading marketing, as we have done in recent years."
British Gas Services installs and maintains domestic central heating and also offers insurance-based products to its costumers. The division has around 10,000 staff.
The British Gas spokeswoman added: "We will be consulting with the people in our commercial team, which includes our marketing and sales function, about a proposed reduction in the number of people employed in that team."
All the "Big Six" suppliers have been hit by criticism for hiking their energy prices, with British Gas increasing domestic gas bills by 18% and electricity bills by 16% in August.
Labour leader Ed Miliband has slammed the big six energy firms and has laid out plans to break up the firms to reduce their stranglehold on the market.
The job cuts come after Marketing revealed British Gas was quietly rolling out a new visual identity in a "zero-cost" exercise.
Follow Matthew Chapman at @mattchapmanUK