Wiltshire's 42,100 tax credits customers are being prompted to renew their claim now through an advertising campaign launched today.
HM Revenue and Customs (HMRC) is sending out 5.8 million tax credits renewals packs which will arrive by June 30.
More than three million of these claims need to be renewed before the deadline for claimants to continue receiving tax credits.
Last year about 650,000 claimants had their money stopped because they did not renew by the July 31 deadline.
Claimants must tell HMRC about any changes to their circumstances that they have not already reported, including changes to working hours, childcare costs and income, or if a partner has moved in.
This year, as well as being able to renew by post and by phone, claimants with no changes to report are also able to renew online, via GOV.UK
Nick Lodge, HMRC’s director general of benefits and credits, said: "People in Wiltshire should check their details and renew early to make sure they get the right money.
"Don't leave it – people who don't renew on time risk losing their payments."
Before checking their form or calling HMRC’s Tax Credit Helpline, claimants are urged to have the right documents to hand, for example, payslips, end of year P60 forms and childcare payment details.
The advertising campaign runs throughout June and July on radio, television, bus shelters, and via a mobile app, Spotify and video on demand.
There are 26,400 tax credit claimaints in the Wiltshire Council area, with about 15,700 living in Swindon Council's area.
Claimants can get help and information on tax credits renewals at gov.uk/browse/benefits/tax-credits or call 0345 300 3900.
Tax credits renewals information will be on Twitter under #TaxCredits and #RenewNow, you can follow HMRC on Twitter @HMRCgovuk
HMRC’s also has a flickr channel at www.flickr.com/hmrcgovuk